Sample records for aminopyrine

  1. Bacterial degradation of aminopyrine.


    Blecher, H; Blecher, R; Wegst, W; Eberspaecher, J; Lingens, F


    1. Four strains of bacteria growing with aminopyrine as sole source of carbon were isolated from soil and were identified as strains of Phenylobacterium immobilis. 2. Strain M13 and strain E, the type species of Phenylobacterium immobilis (DSM 1986), which had been isolated by enrichment with chloridazon (5-amino-4-chloro-2-phenyl-2H-pyridazin-3-one) were used to investigate the bacterial degradation of aminopyrine. 3. Three metabolites were isolated and identified as: 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-2-(2,3-dihydro-2,3-dihydroxy-4,6-cyc lohexadien-1-yl)-3H-pyrazol-3-one, 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-2-(2,3-dihydroxyphenyl)-3H-pyrazol-3 -one and 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-3H-pyrazol-3-one. 4. An enzyme extract from cells of strain m13 was shown to further metabolize the catechol derivative of aminopyrine, with the formation of 2-pyrone-6-carboxylic acid. 5. Results indicate that the benzene ring of aminopyrine is the principal site of microbial metabolism.

  2. Kinetics and metabolism of pyrazolones (propyphenazone, aminopyrine and dipyrone)

    PubMed Central

    Volz, Manfred; Kellner, Hans-Martin


    1 Propyphenazone 220 mg was administered orally to volunteers. Maximum plasma concentrations between 1.5 μg/ml and 3.5 μg/ml were found 30 min later. After comparable doses plasma concentrations in dog and rabbit were lower. The distribution volumes were 2 1/kg. 2 The major metabolic route of propyphenazone is demethylation. The main urinary metabolite is the enolglucuronide of N-(2)-demethylprophyphenazone. 3 Aminopyrine is rapidly and almost completely absorbed after oral administration. Maximum plasma concentrations of 10 μg/ml are reached 1.5 h after a 500 mg dose. The biological half-life is 2-3 h, the relative distribution volume 60% on average, and binding to plasma proteins approximately 15%. 4 Unchanged aminopyrine is only excreted in small quantities. The major routes of metabolism are demethylation (4-methylaminoantipyrine and 4-aminoantipyrine) and acylation (4-acetyl and 4-formylaminoantipyrine). There are other biotransformation products. 5 After oral administration of [14C]-dipyrone 480 mg the maximum serum concentration of 13.4±0.8 μg/ml occurred at 1-1.5 hours. 6 Dipyrone was not detectable in serum or urine. Four of seven metabolites were identified, and were identical with the main metabolites of aminopyrine. PMID:7002187

  3. Preliminary studies of a canine 13C-aminopyrine demethylation blood test.

    PubMed Central

    Moeller, E M; Steiner, J M; Williams, D A; Klein, P D


    The objectives of this study were to determine whether a 13C-aminopyrine demethylation blood test is technically feasible in clinically healthy dogs, whether oral administration of 13C-aminopyrine causes a detectable increase in percent dose/min (PCD) of 13C administered as 13C-aminopyrine and recovered in gas extracted from blood, and whether gas extraction efficiency has an impact on PCD. A dose of 2 mg/kg body weight of 13C-aminopyrine dissolved in deionized water was administered orally to 6 clinically healthy dogs. Blood samples were taken from each dog 0, 30, 60, and 120 min after administration of the 13C-aminopyrine. Carbon dioxide was extracted from blood samples by addition of acid and analyzed by fractional mass spectrometry. None of the 6 dogs showed any side effects after 13C-aminopyrine administration. All 6 dogs showed a measurable increase of the PCD in gas samples extracted from blood samples at 30 min, 60 min, and 120 min after 13C-aminopyrine administration. Coefficients of variation between the triplicate samples were statistically significantly higher for the %CO2, a measure of extraction efficiency, than for PCD values (P < 0.0001). The 13C-aminopyrine demethylation blood test described here is technically feasible. Oral administration of 13C-aminopyrine did not lead to gross side effects in the 6 dogs. Clinically healthy dogs show a measurable increase of PCD in gas extracted from blood samples after oral administration of 13C-aminopyrine. Efficiency of CO2 extraction from blood samples does not have an impact on PCD determined from these blood samples. This test may prove useful to evaluate hepatic function in dogs. PMID:11227194

  4. Aminopyrine metabolism by multiple forms of cytochrome P-450 from rat liver microsomes: simultaneous quantitation of four aminopyrine metabolites by high-performance liquid chromatography.


    Imaoka, S; Inoue, K; Funae, Y


    Four aminopyrine metabolites generated by hepatic microsomes were simultaneously assayed by high-performance liquid chromatography. The metabolites were 4-monomethylaminoantipyrine (MAA), 4-aminoantipyrine (AA), 3-hydroxymethyl-2-methyl-4-dimethylamino-1-phenyl-3-pyrazoline-5-one (AM-OH), and one unidentified metabolite. MAA was the major metabolite generated by the microsomes; its formation was induced by phenobarbital but not by 3-methylcholanthrene. Female rats had lower N-demethylation activity of aminopyrine than male rats. The production of AA by microsomes was low. The formation of AM-OH was strongly induced by phenobarbital, but treatment with 3-methylcholanthrene reduced its formation. These differences in the microsomal aminopyrine monooxygenase activity are dependent on the relative amounts of the individual cytochrome P-450 isozymes. Therefore, we examined aminopyrine metabolism in a reconstituted system with purified cytochrome P-450s. P-450 UT-2 (P-450h) had high aminopyrine N-demethylation and hydroxylation activities, but P-450 F-2 (P-450i) had low N-demethylation activity and no hydroxylation activities, but P-450 F-2 (P-450i) had low N-demethylation activity and no hydroxylation activity. P-450 PB-4 (P-450b) and P-450 PB-5 (P-450e) had high aminopyrine hydroxylation activity and their N-demethylation activity also was high. The 3-methylcholanthrene-inducible forms P-450 MC-1 (P-450d) and MC-5 (P-450c) had aminopyrine N-demethylation activity but no hydroxylation activity. P-450 UT-4 (RLM2) is a unique form that produced a large amount of the unknown metabolite. P-450 UT-7 had the highest N-demethylation activity. Addition of cytochrome b5 to the reconstituted system enhanced the aminopyrine hydroxylation activities of P-450s UT-1, UT-2, PB-2, and PB-5. Also, the N-demethylation activities of P-450s UT-1, PB-1, PB-2, and MC-1 were increased by cytochrome b5. Metyrapone inhibited the catalytic activities of P-450s PB-4, PB-5, MC-1, and MC-5, and

  5. Impairment of aminopyrine clearance in aspirin-damaged canine gastric mucosa

    SciTech Connect

    Miller, T.A.; Henagan, J.M.; Loy, T.M.


    Using an in vivo canine chambered stomach preparation, the clearance of (/sup 14/C)aminopyrine across mucosa when intravenously infused and the back-diffusion of this substance from gastric lumen to mucosa when topically applied to gastric epithelium were evaluated in aspirin-damaged gastric epithelium. In mucosa damaged by either 20 mM or 40 mM aspirin, the recovery of (/sup 14/C)aminopyrine, when topically mixed with acid (pH . 1.1) perfusate solution, was not significantly different from nondamaged control mucosa. In addition, the degree of ''trapping'' of this substance from back-diffusion was not different in damaged mucosa from that observed in nondamaged epithelium. In contrast, when (/sup 14/C)aminopyrine was intravenously infused, its clearance was significantly impaired in aspirin-damaged mucosa when compared with control studies, as evidenced by the increased ''trapping'' of this substance in injured epithelium. These findings indicate that movement of aminopyrine from plasma to gastric lumen is impaired in damaged epithelium, making the aminopyrine clearance technique an unreliable method to accurately measure absolute gastric blood flow in this experimental setting.

  6. The relationship between aminopyrine breath test and severity of liver disease in cirrhosis

    SciTech Connect

    Morelli, A.; Narducci, F.; Pelli, M.A.; Farroni, F.; Vedovelli, A.


    Twenty-two patients with cirrhosis were evaluated by the 2 hr.-(C14)-aminopyrine breath test, the conventional liver tests and two systems for grading the severity of liver disease. Twenty-three patients with noncirrhotic liver disease and 15 controls were also studied. Reduced 14CO2 values were found in 21 of the 22 cirrhotic patients and seven of those had noncirrhotic liver disease associated with severe functional reserve impairment. The values in patients with minor liver diseases or cholestasis were normal. In the cirrhotic patients 2 hr.-(C14)-aminopyrine breath test scores correlated with prothrombin time, retention of bromosulfalein, fasting serum bile acid, albumin, bilirubin, serum aspartate aminotransferase and, above all, with the scores of the two clinical rating systems. The 2 hr.-(C14)-aminopyrine breath test was superior to conventional tests in quantifying the degree of hepatic functional reserve and forecasting the prognosis.

  7. Effect of adenosine and adenosine analogs on ( sup 14 C)aminopyrine accumulation by rabbit parietal cells

    SciTech Connect

    Ota, S.; Hiraishi, H.; Terano, A.; Mutoh, H.; Kurachi, Y.; Shimada, T.; Ivey, K.J.; Sugimoto, T. )


    Adenosine receptors that modulate adenylate cyclase activity have been identified recently in a number of tissues. Adenosine A2 receptor is stimulatory to adenylate cyclase, whereas adenosine A1 receptor is inhibitory to adenylate cyclase. We investigated the effect of adenosine and its analogs on (14C)aminopyrine accumulation by rabbit parietal cells. Rabbit gastric mucosal cells were isolated by enzyme digestion. Parietal cells were enriched by nonlinear percoll gradients. (14C)Aminopyrine accumulation was used as an indicator of acid secretion. The effect of 2-chloroadenosine on histamine-stimulated (14C)aminopyrine accumulation was studied. The effects of N-ethylcarboxamideadenosine, 2-chloroadenosine, stable analogs of adenosine, and adenosine on (14C)aminopyrine accumulation were assessed. Cyclic AMP content of parietal cells was determined by radioimmunoassay. Histamine and carbachol, known secretagogues, stimulated (14C)aminopyrine accumulation. 2-Chloroadenosine did not suppress histamine-stimulated (14C)aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine dose dependently increased (14C)aminopyrine accumulation. The order of potency was N-ethylcarboxamideadenosine greater than 2-chloroadenosine greater than adenosine. 8-Phenyltheophylline and theophylline, adenosine-receptor antagonists, or cimetidine did not have significant effects on the increase of AP uptake induced by 2-chloroadenosine. Coadministration of dipyridamole, and adenosine uptake inhibitor, augmented the effect of adenosine on (14C)aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine each induced a significant increase in cellular cyclic AMP. We conclude that there may be adenosine A2 receptors on rabbit parietal cells which modulate gastric acid secretion.

  8. (14C)Aminopyrine breath test in chronic liver disease: preliminary diagnostic implications

    SciTech Connect

    Burnstein, A.V.; Galambos, J.T.


    The (14C)aminopyrine breath test (APBT) score, an estimate of hepatic mixed-oxidase function, was evaluated in 21 consecutive patients wih active nonalcoholic chronic liver diseases. Ten had primary biliary cirrhosis (PBC) and 11 had chronic active hepatitis (CAH). The APBT score was normal or elevated in patients with PBC (P less than 0.001), and lower than normal in CAH patients (P less than 0.01); 10.5 +/- 1.6 and 3.5 +/- 1.86, respectively, vs control 7.65 +/- 1.15 (mean +/- SD). The 11 patients with CAH included two middle-aged women who displayed ambiguous severe intrahepatic cholestasis. There was no overlap between the APBT scores of the 10 PBC and 11 CAH patients. These initial data suggest that the APBT may be helpful in the differentiation of PBC and CAH, including misleading cholestatic forms of CAH.

  9. Influence of different proton pump inhibitors on activity of cytochrome P450 assessed by [(13)C]-aminopyrine breath test.


    Kodaira, Chise; Uchida, Shinya; Yamade, Mihoko; Nishino, Masafumi; Ikuma, Mutsuhiro; Namiki, Noriyuki; Sugimoto, Mitsushige; Watanabe, Hiroshi; Hishida, Akira; Furuta, Takahisa


    Aminopyrine is metabolized by cytochrome P450 (CYP) in the liver. The investigators evaluated influences of different PPIs on CYP activity as assessed by the [(13)C]-aminopyrine breath test ([(13)C]-ABT). Subjects were 15 healthy volunteers with different CYP2C19 status (5 rapid metabolizers [RMs], 5 intermediate metabolizers [IMs], and 5 poor metabolizers [PMs]). Breath samples were collected before and every 15 to 30 minutes for 3 hours after oral ingestion of [(13)C]-aminopyrine 100 mg on day 8 of each of the following regimens: control; omeprazole 20 mg and 80 mg, lansoprazole 30 mg, and rabeprazole 20 mg. Changes in carbon isotope ratios in carbon dioxide ((13)CO(2)/(12)CO(2)) in breath samples were measured by infrared spectrometry and expressed as delta-over-baseline (DOB) ratios (‰). Mean areas under the curve of DOB from 0 to 3 h (AUC(0-3h) of DOB) were significantly decreased by omeprazole 20 mg and lansoprazole 30 mg but not by rabeprazole 20 mg. Conversely, higher PPI dose (ie, omeprazole 80 mg) seemed to further decrease AUC(0-3h) of DOB in RMs but increased it in PMs. Omeprazole and lansoprazole at the standard doses inhibit CYP activity but rabeprazole does not, whereas high-dose omeprazole seems to induce CYPs.

  10. Breath /sup 14/CO2 after intravenous administration of (/sup 14/C)aminopyrine in liver diseases

    SciTech Connect

    Pauwels, S.; Geubel, A.P.; Dive, C.; Beckers, C.


    The determination of of /sup 14/CO2 in breath after oral administration of (/sup 14/C)aminopyrine has been proposed as a quantitative liver function test. In order to shorten the procedure and avoid misinterpretations related to variable rates of intestinal absorption, the (/sup 14/C)aminopyrine breath test (ABT) was performed after intravenous administration of (/sup 14/C)aminopyrine in 21 controls and 89 patients with biopsy-proven liver disease. The specific activity of the first hour sample corrected for body weight (SA1) was the most discriminant expression of breath data. The SA1 value, expressed as the percentage of the administered dose, was 0.86 +/- 0.1% (mean +/- SD) in controls and significantly less in patients (0.46 +/- 0.31%). Low values were observed in patients with untreated chronic active hepatitis (0.16 +/- 0.13%), alcoholic cirrhosis (0.2 +/ 0.15%0, and untreated postnecrotic cirrhosis (0.47 +/- 0.17%). In contrast, normal values were obtained in chronic persistent hepatitis (0.86 +/- 0.13%) and 58% of noncirrhotic alcoholic liver diseases (0.83 +/- 0.27%). The results of duplicate studies were reproducible and SA1 correlated with other conventional liver function tests, including 45-min BSP retention. Among these, ABT was the most sensitive screening test for the presence of cirrhosis, especially in alcoholic patients, where it allowed a sharp distinction between cirrhotic and noncirrhotic cases. The results obtained in chronic hepatitis suggested that ABT may provide a reliable index of the activity of the disease. In our hands, intravenous ABT, performed over a 1-hr period, was a fast, sensitive, and discriminant liver function test.

  11. Transformation of aminopyrine in the presence of free available chlorine: Kinetics, products, and reaction pathways.


    Cai, Mei-Quan; Feng, Li; Zhang, Li-Qiu


    Aminopyrine (AMP) has been frequently detected in the aquatic environment. In this study, the transformation mechanism of AMP by free available chlorine (FAC) oxidation was investigated. The results showed that FAC reacted with AMP rapidly, and a 74% elimination was achieved for 1.30 μM AMP after 2 min at 14.08 μM FAC dose. AMP chlorination was strongly pH-dependent, and its reaction included second- and third-order kinetic processes. Three active FAC species, including chlorine monoxide (Cl2O), molecular chlorine (Cl2), and hypochlorous acid (HOCl), were observed to contribute to AMP degradation. The intrinsic rate constants of each FAC species with neutral (AMP(0)) and cation (AMP(+)) species were obtained by kinetic fitting. Cl2O exhibited the highest reactivity with AMP(0) (kAMP0, Cl2O = (4.33 ± 1.4) × 10(9) M(-1)s(-1)). In addition, Cl2 showed high reactivity (10(6)-10(7) M(-1)s(-1)) in the presence of chloride, compared with HOCl (kAMP+, HOCl = (5.73 ± 0.23) × 10(2) M(-1)s(-1), kAMP0, HOCl = (9.68 ± 0.96) × 10(2) M(-1)s(-1)). At pH 6.15 and 14.08 μM FAC dose without chloride addition, the contribution of Cl2O reached to the maximum (33.3%), but in the whole pH range, HOCl was the main contributor (>66.6%) for AMP degradation. The significance of Cl2 was noticeable in water containing chloride. Moreover, 11 transformation products were identified, and the main transformation pathways included pyrazole ring breakage, hydroxylation, dehydrogenation, and halogenation.

  12. Specific inhibition by prostaglandins E2 and I2 of histamine-stimulated [14C]aminopyrine accumulation and cyclic adenosine monophosphate generation by isolated canine parietal cells.

    PubMed Central

    Soll, A H


    The effects of prostaglandins E2 and I2 on accumulation of [14C]aminopyrine and the generation of cyclic AMP by fractions of dispersed canine gastric mucosal cells, enriched in their content of parietal cells, have been studied. The parietal cell content of the fractions was enriched to between 43 and 70% using an elutriator rotor. The accumulation of [14C]aminopyrine was used as the index of parietal cell response to stimulation. Prostaglandin E2 (PGE2, 0.1 nM-0.1 mM) inhibited histamine stimulated aminopyrine uptake but did not block the response to carbachol, gastrin, or dibuturyl cyclic AMP. PGE2 did, however, inhibit aminopyrine uptake stimulated by carbachol and gastrin when the response to these agents was potentiated by histamine. PGE2 (0.1 NM-0.1 mM) inhibited histamine-stimulated cyclic AMP production in a dose-dependent fashion with maximal inhibition at 1 microM PGE2. Prostacyclin also inhibited both histamine-stimulated aminopyrine accumulation and histamine-stimulated cyclic AMP production. In the absence of added histamine, PGE2 in concentrations above 1 microM and prostacyclin in concentrations above 10 microM stimulated cyclic AMP production, probably by acting on the nonparietal cells as shown in previous studies. These present data are consistent with the hypothesis that prostaglandins E2 and I2 inhibit the response of isolated parietal cells to histamine by specifically blocking histamine-stimulated cyclic AMP production. PMID:6154063

  13. Prostaglandin E2 inhibition of secretagogue-stimulated (/sup 14/C)aminopyrine accumulation in rat parietal cells: a model for its mechanism of action

    SciTech Connect

    Rosenfeld, G.C.


    Prostaglandin E2 (PGE2) differentially inhibited histamine and isoproterenol stimulation of (/sup 14/C)aminopyrine accumulation in rat parietal cell preparations. Low concentrations of PGE2 decreased the maximum response to isoproterenol whereas higher concentrations increased the EC50 of histamine with only a modest effect on the maximum response. Also, PGE2 potentiated dibutyryl cyclic AMP stimulation of aminopyrine accumulation in either the absence or presence of carbachol. In contrast, PGE2 inhibited potentiation between carbachol and histamine due to its inhibitory effect on histamine and possibly also to an inhibitory effect on cholinergic activity. Islet activating protein prevented the inhibitory actions of PGE2. To account for these results a model is presented based on the recent proposal by Gilman of an interaction between components of adenylyl cyclase stimulatory and inhibitory guanine nucleotide binding proteins.

  14. Measurement of 7-methylguanine as an estimate of the amount of dimethylnitrosamine formed following administration of aminopyrine and nitrite to rats

    SciTech Connect

    Gombar, C.T.; Zubroff, J.; Strahan, G.D.; Magee, P.N.


    A dose-related increase in the excretion of 7-(methyl-/sup 14/C)methylguanine ( (/sup 14/C)m7Gua) following p.o. administration of di(methyl-/sup 14/C)methylnitrosamine to rats. Urine was collected for 24 hr after di(methyl-/sup 14/C)methylnitrosamine administration, and the purines were precipitated from an aliquot of the urine with silver nitrate. Purines were released from the precipitate with HCl, and (/sup 14/C)m7Gua was quantified by chromatography on an Aminex A-6 column. The excretion of (/sup 14/C)m7Gua increased linearly with the dose of dimethylnitrosamine. This relationship was used to estimate the amount of di(methyl-/sup 14/C)methylnitrosamine formed in the reaction of (/sup 14/C)aminopyrine with sodium nitrite in rats gavaged with these compounds. The dose of dimethylnitrosamine was also estimated from the amount of alkylation of liver DNA in the same animals. These estimates usually differed by less than a factor of 2. (/sup 14/C)aminopyrine and sodium nitrite were administered. The possibility of using this assay to obtain data on nitrosation in humans is discussed.

  15. [Quantification of the drug-metabolizing enzyme system in liver diseases: a comparison between antipyrine saliva clearance and the aminopyrine breath test].


    von Mandach, U; Jost, G; Preisig, R


    The metabolic activity of the hepatic cytochrome P450 system was studied in 53 ambulatory subjects. 18 of these were cirrhotics and 23 had non-cirrhotic liver disease, documented by biopsy, serologic, ultrasound or computerized tomography findings, and characterized by quantitative liver function tests, such as galactose elimination capacity and indocyanine green fractional clearance. For comparison, 12 normal control subjects were also included. All subjects were given 10 mg/kg body weight antipyrine and saliva concentrations determined with an HPLC-method at 24 and 48 hours after dosing. Antipyrine saliva clearance (ASC) was calculated according to a two-point method (Cl1), and compared with a one-point method (Cl2) using the 24 h sample only. These subjects also underwent an aminopyrine breath test (ABT), breath samples being collected at regular intervals during 60 minutes following injection of a tracer dose of 1.5 muCi (14C-dimethylamino)antipyrine. Cl1 and Cl2 correlated strongly (r = 0.93). On the basis of smaller variations (particularly in control subjects), better definition of disease severity and convenience and time saving, Cl2 is to be preferred. Comparison of Cl2 with ABT showed that both procedures apparently quantify overlapping enzymatic activities. However, the relationship between Cl2 and ABT values, albeit highly significant (r = 0.72), suggests that only about half of the variables are subject to the same determinant. In addition, a positive intercept of the regression line extrapolated to the Cl2 axis points to quantitatively important extrahepatic breakdown of antipyrine. The results suggest that, in view of the wide variation in normal values (presumably in part influenced by exogenous pollutants), ASC only provides an approximation of hepatic metabolic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Phorbol ester stimulates secretory activity while inhibiting receptor-activated aminopyrine uptake by gastric glands

    SciTech Connect

    Brown, M.R.; Chew, C.S.


    Both cyclic AMP-dependent and -independent secretagogues stimulate pepsinogen release, respiration and H/sup +/ secretory activity (AP uptake) in rabbit gastric glands. 12-O-tetradecanoylphorbol-13-acetate (T), a diacyglycerol analog, activates protein kinase C (PKC) and stimulates secretion in many systems. T stimulated respiration and pepsinogen release by glands and increased AP uptake by both glands and purified parietal cells. However, T reduced AP uptake by glands stimulated with carbachol (C) or histamine (H) with an apparent IC/sub 50/ of 1 nM. Preincubation with T for 30 min produced maximum inhibition which was not reversed by removal of T. T accelerated the decline of the transient C peak while the late steady state response to H was most inhibited. H-stimulated AP uptake was also inhibited by 50 1-oleoyl-2-acetyl-glycerol, a reported PKC activator, but not by the inactive phorbol, 4..cap alpha..-phorbol-12,13-didecanoate. In contrast, T potentiated AP uptake by glands stimulated with submaximal doses of dibutyryl cyclic AMP. These results suggest inhibition by T is a specific effect of PKC activators. The differing effects of T on secretion indicators may result from a dual action of T on receptor and post-receptor intracellular events.

  17. Lipid peroxide formation in microsomes. Relationship of hydroxylation to lipid peroxide formation

    PubMed Central

    Wills, E. D.


    1. Aminopyrine strongly inhibits NADPH-induced lipid peroxide formation in rat liver microsomes, but ascorbate-induced peroxidation is inhibited to a smaller extent. 2. Aminopyrine oxidation is stimulated by Mg2+ but inhibited by Ca2+. Concentrated solutions (10mm) of iron-chelating agents inhibit aminopyrine oxidation, but the more dilute solutions (0·5mm) of chelators that block lipid peroxide formation do not inhibit aminopyrine oxidation. Microsomes prepared from sucrose–EDTA homogenates rapidly oxidize aminopyrine, but do not form lipid peroxide when incubated with ascorbate or NADPH. 3. Aminopyrine oxidation is strongly inhibited by p-chloromercuribenzoate, less by iodoacetamide and weakly by N-ethylmaleimide. The site of action of these compounds is considered to be a ferredoxin-type protein. GSH and cysteine also inhibit. 4. Other drugs oxidized by microsomes such as caffeine, phenobarbitone and hexobarbitone had either no or little effect on lipid peroxide formation, but codeine inhibited. 5. Most aliphatic hydrocarbons, alcohols, ketones and aldehydes did not affect lipid peroxide formation, but chloroform and carbon tetrachloride inhibited. 6. Many aromatic compounds inhibited lipid peroxide formation. Only aromatic acids were without any effect and phenols and amines were very strong inhibitors. 7. Induction of lipid peroxide formation in microsomes by incubation with ascorbate or NADPH or by treatment with ionizing radiation leads to a sharp decline in the ability of microsomes to oxidize aminopyrine or hydroxylate aniline. 8. It is considered that the two processes of hydroxylation and lipid peroxide formation are closely linked in microsomes. They probably depend on the same electron-transport chain, and peroxide formation, which involves membrane disintegration, may be part of the normal membrane remodelling process. PMID:4390103

  18. Effect of carbon monoxide on xenobiotic metabolism in the isolated perfused rabbit lung

    SciTech Connect

    Trela, B.A.


    It was the aim of this study to determine the level and duration of CO exposure necessary to alter mixed function oxidase-mediated activity in the intact lung and to determine the magnitude of this effect. The effect of CO on the mixed function oxidase-mediated activities of aminopyrine, aniline, 4-ipomeanol and p-nitroanisole in isolated perfused rabbit lungs (IPRL) was investigated. Several concentrations of CO were evaluated for their effect on cytochrome P-450-mediated activity in the lung. Both artificial medium and whole blood were utilized as recirculating perfusates. Monomethyl-4-aminoantipyrine was the major metabolite of aminopyrine produced by in vitro hepatic and pulmonary preparations and by the intact lung. Ventilation of isolated rabbit lungs with 7.5% CO for 2.5 hours caused a 40% decrease in the rates of metabolism of both aminopyrine and p-nitroanisole. This level of CO exposure did not alter the cytochrome P-450-mediated metabolism of aniline nor 4-ipomeanol in the intact lung. Aminopyrine metabolism in isolated rabbit lungs perfused with whole blood was also decreased following the administration of 7.5% CO suggesting that the hemoglobin in whole blood affords no protection against CO-induced inhibition of mixed function oxidase activity in the intact lung. The isozyme of cytochrome P-450 which preferentially metabolizes aminopyrine and p-nitroanisole may be more sensitive to CO-induced inhibition than the form(s) which metabolize aniline and 4-ipomeanol.

  19. Regional gastric mucosal blood flow measurements by hydrogen gas clearance in the anesthetized rat and rabbit.


    Leung, F W; Guth, P H; Scremin, O U; Golanska, E M; Kauffman, G L


    Hydrogen gas clearance using 3% hydrogen in air and platinum contact electrodes was employed for measuring antral and corpus mucosal blood flow in anesthetized animals. Significantly greater antral than corpus mucosal blood flow was consistently demonstrated. Corpus but not antral mucosal blood flow showed a significant dose-related increase with intravenous pentagastrin. Vasopressin induced a significant dose-related decrease in both antral and corpus mucosal blood flow. Simultaneous measurement of basal corpus mucosal blood flow by hydrogen gas clearance and of gastric mucosal blood flow by aminopyrine clearance gave similar values, but the changes with intravenous pentagastrin or vasopressin measured by aminopyrine clearance were of a much higher order of magnitude. Hydrogen gas clearance, however, reflected changes in left gastric artery blood flow much more closely than did aminopyrine clearance. Therefore, we conclude that the hydrogen gas clearance technique as described is valid for measuring regional gastric mucosal blood flow. It is safe and has potential application in human studies.

  20. Cyclic AMP-dependent phosphorylation in the control of biotransformation in the liver.


    Bánhegyi, G; Garzó, T; Mészáros, G; Faragó, A; Antoni, F; Mandl, J


    The possibility of a short-term cAMP-dependent regulation of mixed-function oxidation and of glucuronide formation was investigated in isolated mouse hepatocytes and in mouse liver microsomal membranes. N6, O2-dibutyryl cAMP (in accordance with its increasing effect on gluconeogenesis) decreased aminopyrine oxidation and p-nitrophenol conjugation in isolated hepatocytes, while the phenolphthalein conjugation remained unaltered. Similar to dibutyryl cAMP the Ca2+ ionophore A 23187 also decreased aminopyrine oxidation. In cell-free systems the phosphorylation of isolated microsomal membranes by the exogenous cAMP-dependent protein kinase was inhibitory on aminopyrine oxidation and p-nitrophenol glucuronide formation but aniline oxidation and phenolphthalein glucuronidation were not affected. The correlation between the negative cAMP-dependent control of certain processes of biotransformation and the positive cAMP-dependent regulation of gluconeogenesis is discussed.

  1. Effect of a single oral dose of methanol, ethanol and propan-2-ol on the hepatic microsomal metabolism of foreign compounds in the rat.

    PubMed Central

    Powis, G


    Methanol and ethanol administered to rats as a single oral dose increased aniline hydroxylation by the hepatic microsomal fraction by a maximum of 169 and 66% respectively, whereas aminopyrine demethylation was inhibited by 51 and 61%. The concentration of microsomal cytochrome P-450, and the activities of NADPH-cytochrome c reductase and NADPH-cytochrome P-450 reductase were unchanged. Propan-2-ol, administered as a single oral dose, increased microsomal aniline hydroxylation by 165% and increased aminopyrine demethylation by 83%. The concentration of cytochrome P-450 was unchanged whereas NADPH-cytochrome c reductase and NADPH-cytochrome P-450 reductase were both increased by 38%. Methanol, ethanol and propan-2-ol administration resulted in a decreased type I spectral change but had no effect on the reverse type I spectral change. Methanol administration decreased the type II spectral change whereas ethanol and propan-2-ol had no effect. Cycloheximide blocked the increases in aniline hydroxylation and aminopyrine demethylation but could not completely prevent the decreases in aminopyrine demethylation. The increases in aniline hydroxylation were due to an increase in V, but Km was unchanged. The ability of acetone to enhance and compound SKF 525A to inhibit microsomal aniline hydroxylation was decreased by the administration of all three alcohols. The decrease in the metabolism of aminopyrine may result from a decrease in the binding to the type I site with a consequent failure of aminopyrine to stimulate the reduction of cytochrome P-450. Methanol administration may lead to an increase in aniline hydroxylation because of a failure of aniline to inhibit cytochrome P-450 reduction. PMID:168885

  2. Autoantibody to the gastrin receptor in pernicious anemia

    SciTech Connect

    de Aizpurua, H.J.; Ungar, B.; Toh, B.H.


    The authors examined serum IgG fractions from 20 patients with pernicious anemia and 25 control subjects for their capacity to inhibit binding of (/sup 125/I)15-leu human gastrin-17 to parietal-cell-enriched gastric mucosal cells. IgG fractions from six patients reduced gastrin binding by 45.6 +/- 12.2 per cent, as compared with a reduction of 1.8 +/- 0.7 per cent by fractions from the 25 controls. The fractions from these six patients also reduced gastrin-stimulated (/sup 14/C)aminopyrine uptake by gastric cells (an index of gastric acid secretory activity in vitro) by 50.2 +/- 8.4 per cent (mean +/- S.D.), as compared with 9.2 +/- 4.1 per cent for the controls. IgG fractions from six other patients that did not reduce gastrin binding also inhibited gastrin-stimulated (/sup 14/C)aminopyrine uptake, by 48.1 +/- 9.1 per cent. These reductions in gastrin binding and aminopyrine uptake were abolished by absorption of the IgG fractions with suspensions of viable gastric mucosal cells but not by absorption with liver or kidney cells. The IgG fractions did not inhibit (/sup 3/H)histamine binding or histamine-stimulated (/sup 14/C)aminopyrine uptake. These results suggest that serum IgG from some patients with pernicious anemia contains autoantibodies to the gastrin receptor.

  3. Effects of Anti-Inflammatory Drugs in Shock Caused by Injection of Living E. Coli Cells

    DTIC Science & Technology

    Injection of live E . coli organisms to dogs iv causes a lethal shock. Administrations of anti-inflammatory drugs (indomethacin, aminopyrine...the injection of E . coli were significantly different in the treated animals from those in the control group. Some of the other agents tested were

  4. Comparative effects of medetomidine enantiomers on in vitro and in vivo microsomal drug metabolism.


    Pelkonen, O; Puurunen, J; Arvela, P; Lammintausta, R


    The effects of dexmedetomidine, a selective alpha 2-adrenoceptor agonist, and its levo enantiomer (MPV-1441), on in vitro microsomal P450-dependent drug-metabolizing activities as well as on in vivo aminopyrine elimination and hexobarbital sleeping time were studied. Both enantiomers inhibited the oxidative metabolism of several model substrates and testosterone in rat liver microsomal incubations. Microsomal activities derived from control animals or rats pretreated with phenobarbital were more sensitive to inhibitory effects of dexmedetomidine than those from rats treated with 3-methylcholanthrene. Enzyme activities in human liver microsomes were also inhibited by dexmedetomidine. Retardation of the elimination of aminopyrine was dose-dependent; elimination was marginally retarded with doses up to 100 micrograms/kg (from 17 to 23 min.; both enantiomers). Higher doses of the levo enantiomer prolonged aminopyrine half-life to 78 (1 mg/kg) and 162 min. (10 mg/kg). The hexobarbital sleeping time was prolonged by the dose of 1 mg/kg of the levo enantiomer (128 min. versus 20 min. in controls), while the dose of 0.1 mg/kg had no effect (23 versus 20 min.). These studies indicate that both enantiomers of medetomidine are inhibitors of microsomal drug metabolism in vitro, but significant effects on aminopyrine elimination or hexobarbital sleeping time are apparent only at doses, which do not allow the use of dexmedetomidine because of excessive sedative effect.

  5. Effect of ethanol on acid secretion by isolated gastric glands from rabbit

    SciTech Connect

    Reichstein, B.J.; Okamoto, C.; Forte, J.G.


    Isolated gastric glands from rabbit, as well as basolateral and microsomal membranes derived therefrom, were used to examine the effect of ethanol on several parameters related to acid secretion. Low concentrations of ethanol, 0.2%-5% (vol/vol), had no effect on basal aminopyrine accumulation by isolated gastric glands but significantly potentiated aminopyrine accumulation stimulated by histamine. In contrast, this dose range of ethanol inhibited aminopyrine accumulation stimulated by forskolin or dibutyryl-cyclic adenosine monophosphate. This dose range of ethanol produced a similar effect on adenylate cyclase activity of basolateral membranes from isolated gastric glands, with potentiation of histamine stimulation and inhibition of forskolin stimulation. Low-dose ethanol was found to produce increased proton permeability of the apical membrane of the parietal cell but had no effect on hydrogen-potassium-stimulated adenosine triphosphatase activity. Ethanol (10%) significantly inhibited all parameters of acid secretion studied. Ethanol has a biphasic effect on acid secretion with potentiation of histamine-stimulated aminopyrine accumulation and adenylate cyclase activity at low doses and inhibition of all parameters of acid secretion at high doses.

  6. A micromethod for the assay of cellular secretory physiology: Application to rabbit parietal cells

    SciTech Connect

    Adrian, T.E.; Goldenring, J.R.; Oddsdottir, M.; Zdon, M.J.; Zucker, K.A.; Lewis, J.J.; Modlin, I.M. )


    A micromethod for investigating secretory physiology in isolated cells was evaluated. The method utilized a specially designed polycarbonate incubation chamber to provide constant oxygenation to cells incubating in a 96-well microtiter plate. Cells were rapidly separated from media by vacuum filtration. Isolated parietal cells were utilized to demonstrate the versatility of the method for assay of intracellular accumulation of ({sup 14}C)-aminopyrine, secretion of intrinsic factor into the medium, and assay of intracellular cAMP. Histamine stimulated the uptake of ({sup 14}C)aminopyrine and intrinsic factor secretion in a sustained and linear fashion. At the end of the 2-h period uptake of aminopyrine and secretion of intrinsic factor were increased 17- and 5-fold, respectively. This response to histamine was accompanied by a rapid and sustained 3-fold rise in intracellular cyclic AMP. In contrast, carbamylcholine caused a transient increase in ({sup 14}C)aminopyrine accumulation and intrinsic factor secretion which was most pronounced during the first 10 min and had almost ceased by 30 min. Carbamylcholine had no effect on intracellular cAMP levels. This new method, which can handle 400 replicates using parietal cells from the fundic mucosa of a single rabbit, is suitable for studying the time course of intracellular events which accompany general secretory processes.

  7. Generation of oxygen free radicals during the metabolism of cyclosporine A: a cause-effect relationship with metabolism inhibition.


    Serino, F; Grevel, J; Napoli, K L; Kahan, B D; Strobel, H W


    A better understanding of the mechanism of lipid peroxidation during the metabolism of cyclosporine A (CsA) might help explain the toxicities of this immunosuppressive drug on various organs. Our in vitro work used microsomes prepared from livers of phenobarbital-induced male rats. The incubations (total volume 1ml) also contained a NADPH regenerating system and substrate (i.e., CsA, carbon tetrachloride, or aminopyrine) dissolved in ethanol. Lipid peroxidation was inferred from the presence of malondialdehyde (MDA) which was detected by the thiobarbituric acid assay. The formation of CsA hydroxylated metabolites (AM9 and AM1) was monitored by liquid chromatography. The activity of the microsomal incubation was confirmed by measurements of MDA and formaldehyde production caused by increasing concentrations of CsA, carbon tetrachloride, and aminopyrine. The occurrence of hydroxylated metabolites was not coupled to the production of MDA. Aminopyrine could inhibit MDA production by CsA, but CsA could not reduce the formation of formaldehyde by aminopyrine. Erythromycin, a competitor for the binding site of CsA on cytochrome P450, reduced MDA production by CsA, and CsA inhibited formaldehyde production by erythromycin. Interaction studies with SKF 525A, ketoconazole, superoxide dismutase, catalase, alpha-tocopherol, and reduced glutathione confirmed the role of cytochrome P450 and the presence of activated oxygen species as a source of microsomal peroxidation which in return may explain the inhibitory effect of CsA on cytochrome P450 itself.

  8. Non-migrainous headache for the evaluation of oral analgesics

    PubMed Central

    Graffenried, B. v.; Nüesch, E.


    1 Eight double-blind, randomized, placebo-controlled, single-dose, cross-over studies were carried out to evaluate the usefulness of testing the acute analgesic effect of drugs in out-patients with non-migrainous headache. 2 The reference compounds were either (1) aspirin, (2) a combination of aminopyrine, caffeine and butalbarbital (Optalidon®), and (3) a combination of (2) with dihydroergotamine (Tonopan®). 3 The test compounds were (1) proquazone, (2) fluproquazone and (3) and (4), new formulations of Optalidon® and Tonopan® in which the aminopyrine was replaced by propyphenazone. They were all found to be active. 4 A significant, dose-response relationship was established for aspirin (250, 500 and 1000 mg). 5 It is concluded that the non-migrainous headache model is a practical, reproducible and sensitive method for the investigation of the acute efficacy of analgesics. PMID:7002183

  9. Measurement of gastric mucosal blood flow in dogs by the /sup 99m/Tc 4-methylaminophenazone clearance technique

    SciTech Connect

    Doebroente, Z.; Lang, J.; Sagi, I.; Varro, V.


    In anesthetized dogs, correlation was found between the /sup 99m/Tc 4-methylaminophenazone and aminopyrine clearance measured in the same animal after administration of the gastric secretory stimulants vasopressin or glucagon. Similar correlation was observed between the /sup 99m/Tc 4-methylaminophenazone and /sup 14/C aminopyrine clearance during histamine administration. The clearance values were always corrected by the actual degree of dissociation of the radioactive molecules. The results suggest that /sup 99m/Tc 4-methylaminophenazone is suitable to study circulatory changes in human gastric mucosa. Advantages of this compound include a much lower dose of radiation absorbed by the patient and his surroundings, a simplified measurement technique, and considerably reduced expenses.

  10. Regulation of the Cinnamate 4-Hydroxylase (CYP73A1) in Jerusalem Artichoke Tubers in Response to Wounding and Chemical Treatments.

    PubMed Central

    Batard, Y.; Schalk, M.; Pierrel, M. A.; Zimmerlin, A.; Durst, F.; Werck-Reichhart, D.


    trans-Cinnamate 4-hydroxylase (C4H) is a plant-specific cytochrome (P450) that is encoded by the gene CYP73A and catalyzes the second step of the multibranched phenylpropanoid pathway. Increases in C4H activity in response to physical and chemical stresses have been well documented, but the mechanism of these increases has never been studied in detail. This paper reports on the regulatory mechanism controlling C4H activity in Jerusalem artichoke (Helianthus tuberosus) tubers in response to wounding and chemical treatments. We compared induction of C4H and other P450-catalyzed activities. C4H was moderately induced by chemicals relative to other P450s. Increases in enzyme activity, C4H protein, and transcripts were quantified and compared in tuber tissue 48 h after wounding and chemical treatments. Our data suggest that induction of the enzyme activity results primarily from gene activation. Time-course experiments were performed after wounding and aminopyrine treatment. Compared with wounded tissues, aminopyrine triggered an additional and delayed peak of transcript accumulation. The timing of the induced changes in activity, protein, and transcripts confirms that C4H induction results primarily from an increase in CYP73A1 mRNA, in both wounded and aminopyrine-treated tissues. However, posttranscriptional mechanisms might also contribute to the regulation of C4H activity. PMID:12223655

  11. Hepatic effects of phthalate esters.

    PubMed Central

    Seth, P K


    Di(2-ethylhexyl) phthalate (DEHP), a commonly used plasticizer and microchemical environmental pollutant, produces subtle changes in hepatic function as judged by increase in liver weight and morphological and biochemical alterations. It can modify the biological response of drugs and other xenobiotics. Such interactions appear to occur at the pharmacokinetic phase, as DEHP was found to alter the activity of microsomal drug-metabolizing enzymes and ethanol metabolism. DEHP produced a time- and route-dependent effect on the hepatic cytochrome P-450 contents and activity of aminopyrine N-demethylase, aniline hydroxylase, alcohol dehydrogenase and high and low Km aldehyde dehydrogenases when given orally or intraperitoneally. Under in vitro conditions, DEHP produced no effect on the activity of aminopyrine N-demethylase or aniline hydroxylase, while mono(2-ethylhexyl) phthalate (MEHP) and 2-ethylhexanol (2-EH) significantly inhibited their activity at concentrations ranging from 2.5 to 15.0 mM. Activity of aminopyrine N-demethylase and aniline hydroxylase was also inhibited by dimethyl phthalate (DMP) and dibutyl phthalate (DBP) after a single oral administration. In view of the possibility of the human exposure to phthalates and other xenobiotics simultaneously, these observations are of great significance. PMID:6754361

  12. Mechanism of formation of the thioether conjugate of the bladder carcinogen 2-amino-4-(5-nitro-2-furyl)-thiazole (ANFT).


    Lakshmi, V M; Zenser, T V; Sohani, S; Davis, B B


    The formation of thioether conjugates is an important pathway for inactivation of certain carcinogens. This study assessed the mechanism by which the bladder carcinogen 2-amino-4-(5-nitro-2-furyl)-thiazole (ANFT) forms a glutathione conjugate (ANFT-SG). Peroxidatic metabolism of ANFT, in the presence of glutathione, results in ANFT-SG formation. Both prostaglandin H synthase and horseradish peroxidase can catalyze this reaction. Metabolism of the reducing co-substrates ANFT, phenol, and aminopyrine elicit increases in oxidized glutathione (GSSG). ANFT-SG formation is potentiated by phenol and aminopyrine. tert-Nitrosobutane (tNB), a thiyl radical trap, prevented increases in both GSSG and ANFT-SG. Increasing concentrations of ANFT elicited corresponding increases in both GSSG and ANFT-SG. Peroxidatic metabolism of ANFT in the presence of glutathione, but not in the absence of glutathione, resulted in oxygen uptake. The formation of GSSG and oxygen uptake are consistent with the presence of thiyl radicals during ANFT metabolism. 5,5-Dimethyl-1-pyrroline N-oxide, a thiyl radical trap, was not as effective as tNB in inhibiting the formation of ANFT-SG and GSSG. Ascorbic acid, a reducing cosubstrate and antioxidant, was very effective in preventing ANFT-SG and GSSG formation, while the strong nucleophile methionine was ineffective. To clarify effects of different test agents, their effects on aminopyrine cation radical formation were assessed. Results are consistent with ANFT reacting with thiyl radicals to form ANFT-SG. ANFT appears to be a thiyl radical trap. Peroxidatic metabolism of ANFT probably results in the formation of a cation radical rather than a carbon-centered radical.

  13. Induction of SOS functions in Escherichia coli and biosynthesis of nitrosamine in rabbits by nitrogen dioxide

    SciTech Connect

    Kosaka, H.; Uozumi, M.; Nakajima, T.


    Nitrogen dioxide induced SOS functions in Salmonella typhimurium and Escherichia coli K-12 and was mutagenic in Escherichia coli WP2. When a rabbit was administered aminopyrine intravenously and administered nitrogen dioxide by inhalation, N-nitrosodimethylamine was detected in its blood. Analysis was conducted with /sup 15/N-nitrosodimethylamine as an internal standard by a combination of capillary gas chromatography and mass spectrometry. Accompanying administration of cystamine increased the blood concentration of N-nitrosodimethylamine in the rabbit, suggesting inhibition of its metabolism. Concurrent sulfur trioxide inhalation increased N-nitrosodimethylamine formation in the rabbit.

  14. Microsomal enzyme induction following repeated oral administration of LAAM.


    Masten, L W; Price, S R; Burnett, C J


    The oral administration of 1-alpha-acetylmethadol (LAAM) in the mouse was shown to cause a significant elevation in the hepatic LAAM N-demethylase activity. Compared to the self-induction phenomena found with methadone and propoxyphene, LAAM was three and two times more potent, respectively, on a molar basis than these two structurally similar narcotic analogs. Moreover, microsomal induction by LAAM resulted in significant elevations of aminopyrine N-demethylase and aniline hydroxylase activities. These effects were also correlated with a dose related decrement of pentobarbital sleeping time. Thus LAAM appears to be a relatively potent inducer of microsomal metabolism.

  15. The effects of estrus cycle on drug metabolism in the rat.


    Brandstetter, Y; Kaplanski, J; Leibson, V; Ben-Zvi, Z


    The effect of the female rat estral cycle on microsomal drug metabolism in-vivo and in-vitro has been studied. Two microsomal enzymes, aminopyrine-N-demethylase and aniline hydroxylase showed a greater specific activity (p less than 0.01) in the diestrus phase of the estral cycle while the oxidative enzyme aryl hydrocarbon hydroxylase and the conjugative enzyme, glucuronyl transferase, were not affected. In vivo studies which included theophylline and antipyrine metabolism, and hexobarbital sleeping times showed no difference between the different phases of the estral cycle. Conflicting evidence about the effect of steroid sex hormones on hepatic drug metabolism is discussed.

  16. The oxidation of drugs by fishes

    USGS Publications Warehouse

    Buhler, Donald R.; Rasmusson, Mary E.


    1. Fish liver microsomal systems have been found to catalyze the hydroxylation of aniline and acetanilide, the N-demethylation of aminopyrine and the O-dealkylation of phenacetin.2. These systems are similar to the corresponding mammalian enzymes and they may be considered to be mixed function oxidase since they require NADPH and oxygen. An absolute requirement for oxygen, however, was difficult to demonstrate for the hepatic phenacetin cleavage system from fish.3. Microsomal drug metabolizing systems from fish have temperature optima which are considerably lower than those of corresponding mammalian systems

  17. Responsiveness of beta-escin-permeabilized rabbit gastric gland model: effects of functional peptide fragments.


    Akagi, K; Nagao, T; Urushidani, T


    We established a beta-escin-permeabilized gland model with the use of rabbit isolated gastric glands. The glands retained an ability to secrete acid, monitored by [14C]aminopyrine accumulation, in response to cAMP, forskolin, and histamine. These responses were all inhibited by cAMP-dependent protein kinase inhibitory peptide. Myosin light-chain kinase inhibitory peptide also suppressed aminopyrine accumulation, whereas the inhibitory peptide of protein kinase C or that of calmodulin kinase II was without effect. Guanosine-5'-O-(3-thiotriphosphate) (GTPgammaS) abolished cAMP-stimulated acid secretion concomitantly, interfering with the redistribution of H+-K+-ATPase from tubulovesicles to the apical membrane. To identify the targets of GTPgammaS, effects of peptide fragments of certain GTP-binding proteins were examined. Although none of the peptides related to Rab proteins showed any effect, the inhibitory peptide of Arf protein inhibited cAMP-stimulated secretion. These results demonstrate that our new model, the beta-escin-permeabilized gland, allows the introduction of relatively large molecules, e.g., peptides, into the cell, and will be quite useful for analyzing signal transduction of parietal cell function.

  18. Overnight salivary caffeine clearance: a liver function test suitable for routine use.


    Jost, G; Wahlländer, A; von Mandach, U; Preisig, R


    The feasibility of measuring caffeine clearance from saliva (SCl) was assessed in ambulatory patients with liver disease and in a control group, and the results were compared with quantitative liver function tests. For this purpose, the subjects were given 280 mg caffeine p.o. in decaffeinated coffee powder between noon and 4 p.m., and caffeine concentrations were measured in saliva (using an enzyme immunoassay) before bedtime and upon arising. In the cirrhotics (n = 29), SCl was 0.58 +/- S.D. 0.45 ml per min X kg, thus being reduced to approximately one-third of drug-free, nonsmoking controls (1.53 +/- 0.46, n = 18); although patients with noncirrhotic liver disease showed intermediate values (0.95 +/- 0.47), their reduction in SCl was significant (p less than 0.001). SCl was correlated with indocyanine green fractional clearance, galactose elimination capacity and aminopyrine breath test; however, the closest relationship (Rs = 0.80) was observed with the aminopyrine breath test. It is suggested that the measurement of SCl represents a noninvasive and innocuous procedure for quantifying hepatic microsomal function, and is suitable for routine use. Since a.m. saliva concentrations of caffeine are highly correlated (Rs = -0.94) with SCl, further simplification of the test to a single-point measurement appears possible.

  19. Stimulation of acid secretion and phosphoinositol production by rat parietal cell muscarinic M sub 2 receptors

    SciTech Connect

    Pfeiffer, A.; Rochlitz, H.; Herz, A.; Paumgartner, G. )


    The muscarinic receptor system involved in hydrogen production by enriched rat gastric parietal cells was investigated. Muscarinic receptor density determined by (N-methyl-{sup 3}H)scopolamine binding was 8,100/cell. The receptor appeared to be of the M{sub 2} muscarinic receptor subtype, since it had a low affinity (K{sub d} 189 nM) for the M{sub 1} receptor antagonist pirenzepine compared with atropine. Receptor activation by carbachol rapidly augmented levels of polyphosphoinositides, indicating an activation of phospholipase C. The dose-response relations for the increase in inositol phosphates closely paralleled the binding of carbachol to muscarinic receptors. The inositol phosphate response was antagonized by pirenzepine with a K{sub i} of 177 nM. the stimulation of inositol phosphate levels by carbachol correlated well with the stimulation of ({sup 14}C)aminopyrine uptake, determine as an index of acid secretion. The muscarinic agonists oxotremorine, pilocarpine, and bethanechol elicited partial increases in inositol phosphates at maximal drug concentrations, and these partial increases correlated with their ability to stimulate ({sup 14}C)aminopyrine uptake. These data indicate that inositolpolyphosphates may be a second messenger of M{sub 2} receptors stimulating acid secretion.

  20. Effect of the degree of hydrogenation of dietary fish oil on the trans fatty acid content and enzymatic activity of rat hepatic microsomes.


    Morgado, N; Galleguillos, A; Sanhueza, J; Garrido, A; Nieto, S; Valenzuela, A


    The degree of fat hydrogenation and the trans fatty acid content of the diet affect the fatty acid composition of membranes, and the amount and the activity of some membrane enzymes. We describe the effects of four isocaloric diets containing either sunflower oil (SO, 0% trans), fish oil (FO, 0.5% trans), partially hydrogenated fish oil (PHFO, 30% trans), or highly hydrogenated fish oil (HHFO, 3.6% trans) as fat sources on the lipid composition and the trans fatty acid content of rat hepatic microsomes. We also describe the effect of these diets on the cytochrome P-450 content and on the aminopyrine N-demethylase, aniline hydroxylase, and UDP-glucuronyl transferase microsomal activities. Cytochrome P-450 content was dependent on the degree of unsaturation of the diet, being higher for the FO-containing diet and lower for the HHFO diet. Aminopyrine N-demethylase activity also correlated with the degree of unsaturation of the diet as did the cytochrome P-450 content did (FO > SO > PHFO > HHFO). Aniline hydroxylase activity appeared to be independent of the degree of unsaturation of the dietary fat, but correlated with the trans fatty acid content of the diet, which was also reflected in the trans content of the microsomal membranes. UDP-glucuronyl transferase activity was higher for the FO-containing diet than for the SO diet, showing intermediate values after the PHFO and HHFO diets.

  1. Measurement and pharmacokinetic analysis of imipramine and its metabolite by brain microdialysis.

    PubMed Central

    Sato, Y.; Shibanoki, S.; Sugahara, M.; Ishikawa, K.


    1. The feasibility of the brain microdialysis method for direct measurement and pharmacokinetic study of imipramine (Imip) and its metabolite desipramine (DMI) was investigated in the rat brain. 2. A dialysis tube was inserted into the right striatum of male Wistar rats, which were administered i.p. with 12.5 mg kg-1 Imip. Thirty microliters dialysate was collected every 15 min, and the levels of Imip and DMI were measured by high-performance liquid chromatography with electrochemical detection (h.p.l.c.-e.c.d.). SKF-525A and aminopyrine were concomitantly administered in order to assess their respective effects on the pharmacokinetics of Imip and DMI in the brain. 3. The intracerebral half life (t1/2) of Imip was 2.4 +/- 0.3 h with Imip alone. Premedication with SKF-525A, an inhibitor of drug-metabolizing enzymes, significantly prolonged the t1/2 of Imip, while at the same time production of DMI from Imip was accordingly inhibited. Concomitant administration of aminopyrine did not induce any significant change in the concentrations of Imip, but significantly inhibited the concentrations of DMI through its competitive antagonism in the demethylation pathway. 4. The present results suggest that the brain microdialysis method reflects the intracerebral pharmacokinetics of Imip and DMI well and may be applicable to further pharmacokinetic investigations of psychotropic agents. PMID:8075879

  2. Climbazole is a new potent inducer of rat hepatic cytochrome P450.


    Kobayashi, Y; Suzuki, M; Ohshiro, N; Sunagawa, T; Sasaki, T; Tokuyama, S; Yamamoto, T; Yoshida, T


    We examined the effect of climbazole on the induction of rat hepatic microsomal cytochrome P450 (P450), and compared the induction potency with other N-substituted azole drugs such as clorimazole. We found that climbazole is found to be a potent inducer of rat hepatic microsomal P450 as clorimazole. Induced level of P450 by climbazole was almost similar in extent to clorimazole when compared with other imidazole drugs in a dose- and time-dependent manner. Parallel to the increase in P450, climbazole increased aminopyrine and erythromycin N-demethylase, ethoxycoumarin O-deethylase, and androstenedione 16 beta- and 15 alpha/6 beta hydroxylase activities; however, clorimazole did not induce aminopyrine N-demethylase activity irrespective of its marked increase in P450 content. Immunoblot analyses revealed that climbazole induced CYP2B1, 3A2 and 4A1. The present findings indicate that climbazole is a new potent inducer of hepatic microsomal P450 and drug-metabolizing enzymes like clorimazole, but it may have some differential mechanism(s) for these enzymes' induction in rat liver.

  3. Extracellular calcium and cholinergic stimulation of isolated canine parietal cells.

    PubMed Central

    Soll, A H


    The role of calcium gating in cholinergic stimulation of the function of parietal cells was studied using cells isolated from canine fundic mucosa by treatment with collagenase and EDTA and enriched by velocity separation in an elutriator rotor. Monitoring the accumulation of [14C[ aminopyrine as an index of parietal cell response, stimulation by carbachol, but not by histamine, was highly dependent upon the concentration of extracellular calcium. Incubation of parietal cells in 0-.1 mM calcium, rather than the usual 1.8 mM concentration, reduced the response to 100 microM carbachol by 92 +/- 2%, whereas histamine stimulation was impaired by 28 +/- 5%. A similar reduction in extracellular calcium suppressed the response to gastrin (100 nM) by 67 +/- 7%. The impairment of cholinergic stimulation found at low extracellular calcium concentrations was rapidly reversed with the readdition of calcium. Lanthanum, which blocks calcium movement across membranes, caused a similar pattern of effects on secretagogue stimulation of aminopyrine accumulation, with 100 microM lanthanum suppressing carbachol stimulation by 83 +/- 2%. This concentration of lanthanum suppressed gastrin stimulation by 40 +/- 7% and histamine stimulation by only 12 +/- 9%. Carbachol, but not histamine nor gastrin, stimulated 45Ca++ uptake. The magnitude of carbachol-stimulated calcium uptake correlated with the parietal cell content of the fractions examined (r = 0.88), and was dose responsive over carbachol concentrations from 1 microM to 1 mM. Atropine (100 nM) caused surmountable inhibition, and these effects of carbachol and atropine on calcium uptake correlated with their effects on oxygen consumption (r = 0.93) and [14C]-aminopyrine accumulation (r = 0.90). Cells preloaded with 45Ca++ lost cellular calcium in a time-dependent fashion; however, this rate of egress was not accelerated by treatment with histamine, gastrin, or carbachol, thus failing to implicate mobilization of intracellular calcium

  4. Biodegradation of kerosene by Aspergillus ochraceus NCIM-1146.


    Saratale, Ganesh; Kalme, Satish; Bhosale, Sanjyot; Govindwar, Sanjay


    The filamentous fungus Aspergillus ochraceus NCIM-1146 was found to degrade kerosene, when previously grown mycelium (96 h) was incubated in the broth containing kerosene. Higher levels of NADPH-DCIP reductase, aminopyrine N-demethylase and kerosene biodegradation activities were found to be present after the growth in potato dextrose broth for 96 h, when compared with the activities at different time intervals during the growth phase. NADPH was the preferred cofactor for enzyme activity, which was inhibited by CO, indicating cytochrome P450 mediated reactions. A significant increase in all the enzyme activities was observed when mycelium incubated for 18 h in mineral salts medium, containing cholesterol, camphor, naphthalene, 1,2-dimethoxybenzene, phenobarbital, n-hexane, kerosene or saffola oil as inducers. Acetaldehyde produced by alcohol dehydrogenase could be used as an indicator for the kerosene biodegradation.

  5. Biodegradation of hazardous triphenylmethane dye methyl violet by Rhizobium radiobacter (MTCC 8161).


    Parshetti, Ganesh; Saratale, Ganesh; Telke, Amar; Govindwar, Sanjay


    Rhizobium radiobacter MTCC 8161 completely decolorized methyl violet (10 mg l(-1)) within 8 h both at static and shaking conditions. The decolorization time increased with increasing dye concentration. The effect of different carbon and nitrogen sources on the decolorization of methyl violet was studied. The maximum decolorization was observed in the presence of sucrose (1%) and urea (1%). UV-Visible, HPLC and FTIR analysis of extracted products confirmed biodegradation of methyl violet. The significant increase in the activities of lignin peroxidase and aminopyrine N-demethylase in the cells obtained after decolorization indicated involvement of these enzymes in the decolorization process. In addition to methyl violet, this strain also shows an ability to decolorize various industrial dyes, (red HE7B, yellow 4G, blue 2B, navy blue HE22, red M5B and red HE3B).

  6. Nicotinamide derivatives as a new class of gastric (H+/K+)-ATPase inhibitors. III. Synthesis and gastric antisecretory activity of 2-[(2- and 4-aminobenzyl, and alpha-methylbenzyl)sulfinyl]-N-(4-pyridinyl) -3-pyridinecarboxamides.


    Terauchi, H; Tanitame, A; Tada, K; Nakamura, K; Seto, Y; Nishikawa, Y


    A new series of 2-[(2-aminobenzyl, 4-aminobenzyl, and alpha-methylbenzyl) sulfinyl]-N-(4-pyridinyl)-3-pyridinecarboxamides. was synthesized and evaluated for gastric antisecretory activities. Several of the compounds synthesized exhibited potent inhibitory activities against [14C]aminopyrine accumulation stimulated by dibutyryl cyclic AMP in isolated rabbit parietal cells and histamine-induced gastric acid secretion in pylorus-ligated rats by intraduodenal administration. In particular, the more polar diastereoisomer of 2-[(4-methoxy-alpha-methylbenzyl)sulfinyl] -N-(4-pyridinyl)-3-pyridinecarboxamide (13b) showed in vivo inhibitory activity equivalent or superior to that of omeprazole and was a more selective (H+/K+)-ATPase inhibitor than omeprazole.

  7. Electrochemical reduction of flavocytochromes 2B4 and 1A2 and their catalytic activity.


    Shumyantseva, V V; Bulko, T V; Bachmann, T T; Bilitewski, U; Schmid, R D; Archakov, A I


    The present study shows that cytochromes P450 2B4 and 1A2 with a covalently attached riboflavin (semisynthetic flavocytochromes RfP450 2B4 and RfP450 1A2) can be reduced electrochemically on rhodium-graphite electrodes at a potential of -500 mV (vs Ag/AgCl). In the presence of substrates such as aminopyrine, aniline, 7-ethoxyresorufin, and 7-pentoxyresorufin, N-demethylation, p-hydroxylation, and O-dealkylation reactions proceeded, as was confirmed by product analysis. Rates of electrocatalytically driven reactions are comparable to those obtained using NAD(P)H as the source of reducing equivalents. These results suggest the practicality of developing flavocytochrome P450s as catalysts for oxidation reactions with different classes of organic substrates.

  8. [Determination of six main components in compound theophylline tablet by convolution curve method after prior separation by column partition chromatography

    NASA Technical Reports Server (NTRS)

    Zhang, S. Y.; Wang, G. F.; Wu, Y. T.; Baldwin, K. M. (Principal Investigator)


    On a partition chromatographic column in which the support is Kieselguhr and the stationary phase is sulfuric acid solution (2 mol/L), three components of compound theophylline tablet were simultaneously eluted by chloroform and three other components were simultaneously eluted by ammonia-saturated chloroform. The two mixtures were determined by computer-aided convolution curve method separately. The corresponding average recovery and relative standard deviation of the six components were as follows: 101.6, 1.46% for caffeine; 99.7, 0.10% for phenacetin; 100.9, 1.31% for phenobarbitone; 100.2, 0.81% for theophylline; 99.9, 0.81% for theobromine and 100.8, 0.48% for aminopyrine.

  9. Probe for intracellular concentrations of drugs: delayed fluorescence from acridine orange

    SciTech Connect

    Wardman, P.; Dennis, M.F.; White, J.


    The aim of this work is to develop fluorescent probes that will indicate effective concentrations of therapeutic agents, or endogenous protectors, at important cellular sites. Acridine orange associates with nucleic acids and emits a 'delayed' fluorescence signal. This signal is quenched by oxidants such as oxygen, nitroaryl radiosensitizers, adriamycin and mitomycin-c, and reductants such as thiols, ascorbate and other radioprotectors. The quenching of the acridine orange delayed fluorescence reflects the effective concentration of these therapeutically-important oxidants and reductants near DNA. The relative concentration of basic radiosensitizers such as pimonidazole (Ro 03-8799) near the DNA is greater than that of misonidazole. Thiols quench the delayed fluorescence signal according to the degree of ionization of the thiol function; this may model the reactivity of thiols with guanine radical sites in DNA. Ascorbate and aminopyrine do not quench the delayed fluorescence from cells stained with acridine orange as these compounds are taken up by cells very inefficiently.

  10. Pharmacokinetics of isradipine in patients with chronic liver disease.


    Cotting, J; Reichen, J; Kutz, K; Laplanche, R; Nüesch, E


    The pharmacokinetics of the dihydropyridine calcium antagonist isradipine has been examined in 8 healthy volunteers, 7 patients with non-cirrhotic chronic liver disease (CLD), and 8 patients with biopsy-proven cirrhosis (CIR). Isradipine was simultaneously given orally (12C 5 mg) and i.v. (13C 1 mg). Systemic availability was significantly increased from 17% to 16% in controls and CLD, respectively, to 37% in CIR. The corresponding systemic clearances averaged 1.1, 0.9 and 0.6 l.min-1, the reduction in cirrhotics being significant. Both aminopyrine demethylation capacity, a measure of hepatic microsomal function, and indocyanine green disappearance, a measure of hepatic perfusion, were correlated with the reduction in systemic clearance, and the reduction in oral clearance was correlated with the reciprocal of the serum bile acid concentration. The loss of first-pass extraction should be considered when this calcium antagonist is given perorally in patients with hepatic cirrhosis.

  11. Identification of inhibitory component in cinnamon--O-methoxycinnamaldehyde inhibits CYP1A2 and CYP2E1-.


    Hasegawa, Atsushi; Yoshino, Masaki; Nakamura, Hiroyoshi; Ishii, Itsuko; Watanabe, Toshiko; Kiuchi, Masahiro; Ishikawa, Tsutomu; Ohmori, Shigeru; Kitada, Mitsukazu


    The Cinnamomi Cortex and Ephedra Herba were found to more strongly inhibit aminopyrine N-demethylation in rat liver microsomes compared to other constituents included in Sho-seiryu-to. The component inhibiting drug oxidations catalyzed by CYP1A2 and CYP2E1 was isolated from Cinnamomi Cortex, and was identified as o-methoxycinnamaldehyde (OMCA). When phenacetin and 4-nitrophenol were used as probe substrates for CYP1A2 and CYP2E1, respectively, the OMCA was shown to be a competitive inhibitor against CYP1A2 while it was a mixed type inhibitor against CYP2E1. The inhibitory effect of OMCA on 4-nitrophenol 2-hydroxylation (K(i)=6.3 microM) was somewhat potent compared to that observed on phenacetin O-deethylation (K(i)=13.7 microM) in rat liver microsomes.

  12. Brief maternal deprivation of rats reduces hepatic mixed function oxidase activities

    SciTech Connect

    Vesell, E.S. ); Heubel, F.; Netter, K.J. )


    Deprivation of pups from mother and sibs for 3 min daily from day 5 today 41 of life reduced activities of 4 hepatic mixed function oxidases (MFO) expressed per mg protein in male rats compared to unhandled control rats. These decreases, though generally small, 22.4% and under, reached statistical significance for the substrates aminopyrine, benzphetamine and ethoxycoumarin. This handling procedure did not consistently affect the inductive response to phenobarbital. Previously ignored as a source of variability in response to xenobiotics, handling appears from these results to merit further investigation as such a factor in uninduced rats. Differences among rats in handling could contribute to large day-to-day variations in their metabolism of xenobiotics.

  13. [Determination of six main components in compound theophylline tablet by convolution curve method after prior separation by column partition chromatography

    NASA Technical Reports Server (NTRS)

    Zhang, S. Y.; Wang, G. F.; Wu, Y. T.; Baldwin, K. M. (Principal Investigator)


    On a partition chromatographic column in which the support is Kieselguhr and the stationary phase is sulfuric acid solution (2 mol/L), three components of compound theophylline tablet were simultaneously eluted by chloroform and three other components were simultaneously eluted by ammonia-saturated chloroform. The two mixtures were determined by computer-aided convolution curve method separately. The corresponding average recovery and relative standard deviation of the six components were as follows: 101.6, 1.46% for caffeine; 99.7, 0.10% for phenacetin; 100.9, 1.31% for phenobarbitone; 100.2, 0.81% for theophylline; 99.9, 0.81% for theobromine and 100.8, 0.48% for aminopyrine.

  14. High-resolution MS and MS(n) investigation of ozone oxidation products from phenazone-type pharmaceuticals and metabolites.


    Favier, Maxime; Dewil, Raf; Van Eyck, Kwinten; Van Schepdael, Ann; Cabooter, Deirdre


    Phenazone-type pharmaceuticals, such as aminopyrine, metamizole, phenazone and propyphenazone, are widely used analgesics that have been detected in wastewater treatment plant effluents in μg L(-1) concentrations. Acetamido antipyrine (AAA) and formyl aminoantipyrine (FAA) - the main metabolites of aminopyrine and metamizole - have also been detected in sub μg L(-1) concentrations in environmental water bodies and in resources used to produce drinking water, suggesting their highly persistent character. In this study phenazone, propyphenazone, AAA and FAA were treated with ozone under laboratory conditions and 17 degradation products were identified by an elucidation approach based on high-resolution mass spectrometry (LTQ Orbitrap). Typical oxidation of carbon-carbon double bonds by ozone was observed among other mechanisms of ring opening. It was demonstrated that reactivity of these compounds with ozone is high (rate constants kO3 ranging from 6.5×10(4) to 2.4×10(6) M(-1) s(-1)). The toxicity of the degradation products from ozonation was estimated by quantitative structure-activity relationships (QSAR). It was shown that, when the carbon-carbon double bond is partially oxidized to an epoxy, the toxicity towards fish and daphnids is higher than that of the parent compound. By further oxidizing the molecules, a common degradation product - 1-acetyl-1-methyl-2-phenylhydrazide (AMPH) - was also found to be more toxic than its parent compounds, which is of concern since this compound has previously been reported in environmental waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Wine stimulates gastric acid secretion in isolated rabbit gastric glands via two different pathways.


    Matsuno, K; Tomita, K; Okabe, S


    Alcoholic beverages such as beer and wine are well known to potently stimulate gastric acid secretion, most probably through an increase in circulating gastrin level. The present study examined whether or not wine stimulates gastric acid secretion by a direct effect on parietal cells, enterochromaffin-like (ECL) cells or both. Gastric mucosa was isolated from female Japanese white rabbits and gland specimens were prepared by the collagenase digestion method. Acid secretion was assessed by gland accumulation of [14C] aminopyrine. The effects of red wine, ethanol, non-alcoholic wine and drugs were determined by incubating gastric glands with aminopyrine. Radioactivity in solubilized glands was determined by a liquid scintillation counting. Neither wine nor ethanol (diluted 1 : 10(2) to 1 : 10(4)) had any effect on gastric acid secretion, whereas non-alcoholic wine stimulated acid secretion in a dose-dependent manner. All substances, however, significantly stimulated gastric acid secretion in IBMX (phosphodiesterase inhibitor)-pretreated glands. S-0509 (a CCK-2 receptor antagonist) and atropine had no effect on acid secretion stimulated by wine, ethanol or non-alcoholic wine in IBMX-pretreated glands. Famotidine and omeprazole significantly inhibited the acid secretion resulting from all of the above stimulants. BAPTA (an intracellular Ca2+ chelator) inhibited acid secretion stimulated with wine or ethanol in a dose-dependent manner, but did not inhibit secretion stimulated by non-alcoholic wine. Wine was found to stimulate gastric acid secretion in gastric glands via two pathways, by an ethanol-induced increase in the concentration of intracellular Ca2+ in parietal cells, and by histamine release from ECL cells potentially induced by constituents present in wine.

  16. Rate of alteration of hepatic mixed-function oxidase system in rats fed different dietary fats.


    Ammouche, A; Dinh, L; Youyou, A; Clément, M; Bourre, J M


    Studies were carried out to evaluate and relate the rate of alteration in mixed-function oxidase system with the changes of the fatty acid composition of rat microsomes induced by different dietary lipids. Male weanling rats were fed from day 21 to 120 with a commercial rat diet or a semisynthetic diet containing no fat or 10% fat consisting of peanut-rapeseed oil, sunflower oil, or salmon oil. In rats fed a fat-free diet, the cytochrome P-450 concentration and aniline hydroxylase, aminopyrine N-demethylase, and NADPH-cytochrome-c reductase activities of liver microsomes at 120 days were, respectively, 26, 16, 10, and 24% lesser than those of rats fed the control diet. However, cytochrome b5 concentration and NADH-cytochrome-b5 reductase activity were, respectively, 33 and 43% higher than those of the control group at the same time. When rats were fed the sunflower oil diet, the cytochrome P-450 concentration and NADH-cytochrome-b5 reductase activity at 120 days were, respectively, 11 and 23% lesser than those of control group. But the cytochrome b5 concentration was 10% higher than that of the control group. In rats fed the fish oil diet, the cytochrome P-450 concentration and NADPH-cytochrome-c reductase, aniline hydroxylase, and aminopyrine N-demethylase activities at 120 days were, respectively, 30, 48, 41, and 31% higher than those of rats fed the control diet. These enzymes were correlated very well (0.84 < r < 0.93), P < 0.05 with dietary sigma polyunsaturated fatty acids (n-3).(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Phenylbutazone peroxidatic metabolism and conjugation.


    Lakshmi, V M; Zenser, T V; Mattammal, M B; Davis, B B


    Phenylbutazone, a nonsteroidal anti-inflammatory drug, elicits therapeutic as well as toxic effects by unknown pathways. Phenylbutazone was shown to form a conjugate with the heterocyclic amine bladder carcinogen 2-amino-4-(5-nitro-2-furyl)-thiazole (ANFT). To understand further the reactivity of these compounds, this study was conducted to identify the conjugate formed and determine the mechanism of conjugate formation. Both prostaglandin H synthase and horseradish peroxidase catalyzed conjugate formation. This conjugate was identified by 1H-NMR to be 4-[2-amino-4-(5-nitro-2-furyl)-5-thiazolyl]-4-butyl-1,2-diphenyl-3,5- pyrazolidinedione. Phenylbutazone-mediated oxygen uptake was inhibited by ANFT (0.1 mM) and the spin traps 5,5-dimethyl-1-pyrroline-N-oxide (200 mM) and tert-nitrosobutane (4 mM). By contrast, phenol (0.005 to 0.25 mM) and aminopyrine (0.4 mM) stimulated oxygen uptake. None of these agents mediated oxygen uptake in the absence of phenylbutazone. Conjugate formation was significantly increased by phenol (0.005-0.25 mM) and aminopyrine (0.4 mM), as well as in the absence of oxygen. Conjugate formation was inhibited by 5,5-dimethyl-1-pyrroline-N-oxide (200 mM), tert-nitrosobutane (4 mM), ascorbic acid (2 mM), and 95% oxygen. Horseradish peroxidase initiated conjugate formation at much lower concentrations than it metabolized ANFT. The stoichiometric relationship between phenylbutazone and ANFT, with respect to conjugate formation, was complex. With the concentration of ANFT fixed at 0.05 mM, phenylbutazone exhibited saturation kinetics with a Km of 0.2 mM. In contrast, saturation kinetics were not observed with ANFT.Km values for ANFT varied with the concentration of phenylbutazone used.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Induction of drug metabolizing enzymes in polybrominated biphenyl-fed lactating rats and their pups.


    Moore, R W; Dannan, G A; Aust, S D


    Polybrominated biphenyls (PBBs) cause a mixed-type (phenobarbital- plus 3-methylcholanthrene-like) induction of liver microsomal drug metabolizing enzymes in rats. However, 2,2',4,4',5,5'-hexabromobiphenyl and 2,2',3,4,4',5,5'-heptabromobiphenyl, which together comprise less than 80% of PBBs (FireMaster), were shown to be strictly phenobarbital-type inducers. Other components (unidentified) must therefore cause the 3-methylcholanthrene-like effects. The potential for PBBs to exert effects on neonates through milk was examined. Lactating rats were fed 0, 0.1, 1.0, or 10 ppm FireMaster for the 18 days following delivery, at which time mothers and most pups were sacrificed. Pups nursing from mothers fed 10 ppm PBBs showed significant increases in liver weights and microsomal protein, and both mothers and pups had increased cytochrome P-450, aminopyrine demethylation, benzo[a]pyrene hydroxylation, and UDP-glucuronyltransferase. Pups nursing from rats fed 1.0 ppm had increases in microsomal protein, cytochrome P-450, aminopyrine demethylation, and benzo[a]pyrene hydroxylation, while their mothers were unaffected. Several pups from the 0, 0.1, and 1.0 ppm groups were maintained on their mother's diets, raised, and allowed to mate. Their pups showed much the same responses to PBBs as did the original group of pups. The effects on both generations of adult female rats were also comparable. PBBs cause a mixed-type induction in both lactating rats and their nursing pups; PBB components responsible for both aspects of this induction must be transmitted through milk. Nursing rats are approximately tenfold more sensitive to the effects of PBBs in their mother's diets than are the dams. The approximate no-effect level for microsomal induction in nursing rats is 0.1 ppm PBBs in the diet of the adult.

  19. Response of Japanese quail fed seed meal from sunflowers grown on municipal sludge-amended soil: elevation of cadmium in tissues

    SciTech Connect

    Stoewsand, G.S.; Babish, J.G.; Telford, J.N.; Bahm, C.; Bache, C.A.; Gutenmann, W.H.; Lisk, D.J.


    Sunflowers were grown on soil amended with 224 metric tons/ha of municipal sewage sludge from Syracuse, NY. The yield of sunflower seeds was reduced by 47.2% by the sludge addition. The harvested seeds contained 1.71 ppm dry weight of cadmium. Deoiled seed meal was incorporated as 25 and 50% of semipurified diet and feed to male and female Japanese quail. The concentrations of cadmium were higher in kidney, liver, muscle, and eggs of birds fed the sludge-grown seed meal as compared to control quail. Tissue concentrations of cadmium increased with increasing dietary levels of sludge-grown seed meal. No significant differences were observed between dietary treatments in the activity of hepatic microsomal p-nitroanisole O-demethylase or aminopyrine N-demethylase in the male birds. Additionally, no mutagenic activity, either direct or with metabolic activation, was found in quail eggs. No observable changes in tissue ultrastructure were observed under electron microscopy in any of the treatment groups. There were no significant differences among the dietary treatment groups in feed intake, growth rate, egg production, or egg hatchability.

  20. Serum from patients with pernicious anaemia blocks gastrin stimulation of acid secretion by parietal cells.

    PubMed Central

    de Aizpurua, H J; Ungar, B; Toh, B H


    We examined 51 sera from patients with pernicious anaemia for their capacity to block maximal gastrin stimulation of acid secretion by isolated rodent gastric parietal cells. 14C-aminopyrine accumulation was used as the index of acid secretion in vitro. Sera from patients with pernicious anaemia gave significantly (P less than 0.005) more block of maximal gastrin stimulation of acid secretion (61.7 +/- 37.8%) than sera from 10 patients with systemic lupus erythematosus (19.6 +/- 17.7%), 10 with scleroderma (34.2 +/- 22.3%), five with rheumatoid arthritis (22.4 +/- 15.6%) or 30 from healthy persons (27.4 +/- 12.8%). Maximal histamine stimulation of acid secretion was not inhibited. The blocking factor was present in serum IgG fractions, and serum and IgG fractions gave parallel dose-response and dilution curves. The serum block was abolished by absorption with gastric mucosal cells and correlated with the presence of parietal cell surface autoantibody. We conclude that serum immunoglobulin in pernicious anaemia can block gastrin stimulation of acid secretion and suggest that this block may be mediated by competition with gastrin for surface receptors on parietal cells. PMID:4042425

  1. Performance of a novel atrazine-induced cerebellar toxicity in quail (Coturnix C. coturnix): Activating PXR/CAR pathway responses and disrupting cytochrome P450 homeostasis.


    Xia, Jun; Qin, Lei; Du, Zheng-Hai; Lin, Jia; Li, Xue-Nan; Li, Jin-Long


    Atrazine is well known to be a biologically hazardous substance with toxic effects, but atrazine-induced neurotoxicity remains unclear. The aim of this study was to investigate the mechanisms of atrazine-induced cerebellar toxicity. To determine atrazine-exerted potential neurotoxicity, quails were treated with 50, 250 and 500 mg/kg atrazine by gavage administration for 45 days. Notably, the changes of cytochrome P450 enzyme system (CYP450s) were observed in atrazine-exposed quails. The contents of cytochrome P450 (CYP450) and Cytochrome b5 (Cyt b5) and the activities of NADPH-cytochrome c reductase (NCR), aminopyrin N-demethylase (APND) and aniline-4-hydeoxylase (AH) were increased and erythromycin N-demethylase (ERND) was decreased in quail cerebellum. Nuclear xenobiotic receptors (NXRs) and the transcriptions of NXRs-related target molecules were influenced in cerebellum. Atrazine disrupted the CYP450s balance in quail cerebellum. These results suggested that atrazine-induced cerebellar toxicity in birds was associated with activating PXR/CAR pathway responses and disrupting cytochrome P450 homeostasis. This study provided novel evidences that atrazine exposure induced cerebellar toxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Effects of various compounds on lipid peroxidation mediated by detergent-solubilized rat liver NADPH-cytochrome C reductase.


    Kamataki, T; Sugita, O; Naminohira, S; Kitagawa, H


    A reconstituted lipid peroxidation system containing NADPH-cytochrome c reductase isolated from detergent-solubilized rat liver microsomes was used to determine the effects of several compounds, including drugs, on the lipid peroxidation activity. EDTA and ferrous ion were essential requirements for reconstitution of the activity. The addition of 1,10-phenanthroline to the system containing both EDTA and ferrous ion further enhanced the activity. Pyrocatecol, thymol, p-aminophenol, imipramine, p-chloromercuribenzoate (PCMB) and alpha-tocopherol exhibited strong inhibition, aniline, N-monomethylaniline, aminopyrine, benzphetamine, SKF 525-A and NADP exhibited moderate inhibition, and phenol, benzoic acid, acetanilide and nicotinamide exhibited less or no inhibition at the concentrations lower than 1000 micron M. Metal ions such as Hg+, Hg2+, Co2+, Cu2+, Mn2+ and U6+ inhibited lipid peroxidation strongly. In addition, Cd2+, St2+ and Ca2+ exhibited less potent to moderate inhibition, and Ba2+ and Mg2+ were without effects on the activity. Among sulfhydryl compounds tested, dithiothreitol inhibited lipid peroxidation to a greater extent than did the other three compounds, glutathione, cysteine and mercaptoethanol.

  3. Carbamoylcholine and gastrin induce inositol lipid turnover in canine gastric parietal cells

    SciTech Connect

    Chiba, T.; Fisher, S.K.; Park, J.; Seguin, E.B.; Agranoff, B.W.; Yamada, Tadataka )


    The potential role of inositol phospholipid turnover in mediating acid secretion was examined in a preparation enriched for isolated canine gastric parietal cells. The stimulatory effects of carbamoylcholine (carbachol) and gastrin on parietal cell uptake of ({sup 14}C)aminopyrine were linked to dose- and time-dependent selective reduction in cellular phosphatidylinositol content, although the specific fatty acid composition of the phosphoinositides was not altered. Analysis of ({sup 3}H)inositol phosphates accumulated in cells prelabeled with ({sup 3}H)inositol revealed an increase in labeled inositol trisphosphate by 5 min of incubation with either carbachol or gastrin. Furthermore, after preincubation of parietal cells in medium containing ({sup 32}P)orthophosphate, the two secretagogues elicited a time-dependent decrease in {sup 32}P labeling of phosphatidylinositol 4,5-bisphosphate and concomitant increase in labeling of phosphatidic acid. These data demonstrate that the acid secretagogue actions of carbachol and gastrin are correlated with turnover of cellular inositol phospholipids in a preparation consisting predominantly of parietal cells.

  4. Chloridazon-catechol dioxygenases, a distinct group of meta-cleaving enzymes.


    Schmitt, S; Müller, R; Wegst, W; Lingens, F


    We previously described a new meta-cleaving enzyme, termed chloridazon-catechol dioxygenase. The present paper describes the comparison of this enzyme with the meta-cleaving enzymes of eighteen strains of soil bacteria isolated with various aromatic compounds. Four of these strains were isolated with the herbicide chloridazon, six with the analgeticum aminopyrine and one with the analgeticum antipyrine as sole carbon source. These strains all belonged to a new type of bacteria, called Phenylobacteria. The seven other strains were isolated with aromatic compounds such as toluene, 3-phenylpropionate, benzoate, papaverine and 4-chlorobenzoate, and belonged to various species including Pseudomonas, Acinetobacter and Nocardia. In double diffusion experiments with antibodies, prepared against chloridazon-catechol dioxygenase, extracts from the eleven strains of Phenylobacteria gave a cross reaction, whereas the extracts of the seven other strains showed no reaction. The enzymes of the eleven positive strains showed the same characteristic kinetic behaviour as the previously described enzyme. In contrast to catechol 2, 3-dioxygenase they needed the addition of exogenous Fe2+ ions for activity. On ion-exchange chromatography they emerged at the same buffer concentration as chloridazon-catechol dioxygenase. In polyacrylamide electrophoresis they migrated identically. The linkage map derived from the activities of the various enzymes with 10 different substrates revealed an identity of more than 80% for these eleven enzymes. So the meta-cleaving enzymes of the Phenylobacteria seem to form a distinct group among the non-heme iron-containing dioxygenases.

  5. Biodegradation of malachite green by Brevibacillus laterosporus MTCC 2298.


    Gomare, Sushama S; Parshetti, Ganesh K; Govindwar, Sanjay P


    Brevibacillus laterosporus MTCC 2298 was screened for the decolorization of eight triphenylmethane dyes. Decolorization of malachite green was found to be fastest (87% within 3 hours, at the concentration 0.1 g/L) among the screened dyes. Various triphenylmethane dyes showed differential induction patterns of the dye-degrading enzymes. The activities of the laccase, nicotinamide adenine dinucleotide-dichlorophenolindophenol reductase (NADH-DCIP reductase), malachite green reductase, and aminopyrine N-demethylase were increased in the cell-free extract obtained after decolorization of malachite green. Fourier transform infrared spectral analysis indicated formation of N-demethylated products, including primary and secondary aryl amines. High-performance liquid chromatography analysis confirmed the transformation of malachite green into new metabolites rather than its reduced form, leucomalachite green. Gas chromatography-mass spectroscopy analysis detected new degradation products, such as reduced tetradesmethyl leucomalachite green (m/z 283) and [4-(1-cyclohexyl)-(1'-phenyl)-methyl]-2, 4-hexenoic acid (m/z 282). Complete decolorization of malachite green also was observed by the partially purified laccase from B. laterosporus.

  6. Role of gap junctions on synchronization in human neocortical networks.


    Gigout, S; Deisz, R A; Dehnicke, C; Turak, B; Devaux, B; Pumain, R; Louvel, J


    Gap junctions (GJ) have been implicated in the synchronization of epileptiform activities induced by 4-aminopyrine (4AP) in slices from human epileptogenic cortex. Previous evidence implicated glial GJ to govern the frequency of these epileptiform events. The synchrony of these events (evaluated by the phase unlocking index, PUI) in adjacent areas however was attributed to neuronal GJ. In the present study, we have investigated the effects of GAP-134, a recently developed specific activator of glial GJ, on both the PUI and the frequency of the 4AP-induced epileptiform activities in human neocortical slices of temporal lobe epilepsy tissue. To delineate the impact of GJ on spatial spread of synchronous activity we evaluated the effects of carbenoxolone (CBX, a non-selective GJ blocker) on the spread in three axes 1. vertically in a given cortical column, 2. laterally within the deep cortical layers and 3. laterally within the upper cortical layers. GAP-134 slightly increased the frequency of the 4AP-induced spontaneous epileptiform activities while leaving the PUI unaffected. CBX had no effect on the PUI within a cortical column or on the PUI in the deep cortical layers. CBX increased the PUI for long interelectrodes distances in the upper cortical layers. In conclusion we provide new arguments toward the role played by glial GJ to maintain the frequency of spontaneous activities. We show that neuronal GJ control the PUI only in upper cortical layers. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Induction of rat hepatic P4501A1 by organic extracts from airborne particulate matter in Santiago, Chile.


    Quiñones, L; Gil, L


    1. Organic extracts from particulate matter collected in downtown Santiago, Chile, in 1990 were administered to female Wistar rats. 2. Extracts shifted the maximal absorption wavelength P450 spectra of the reduced-CO complex of hepatic microsomal P450 from 450 to 448 nm, and enhanced the total content of P450. In addition, substantial increases in aryl hydrocarbon hydroxylase, ethoxyresorufin O-deethylase and ethoxycoumarin O-deethylase activities were observed, whereas aminopyrine N-demethylase activity was not affected by treatment. 3. Western blotting using polyclonal antibodies against P4501A isozymes showed the appearance of a distinct and intense P4501A1 band in microsomes from rat pretreated with air particle extracts, and was not observed in microsomes from control rat. On the other hand, the intensity of the P4501A2 isoenzyme was apparently not affected. 4. These findings suggest that the organic extracts from airborne particulate matter modify the composition of rat liver P450 isozymes by inducing those isoforms responsible for the activation of precarcinogenic to carcinogenic agents.

  8. Quantification of 1-aminopyrene in human urine after a controlled exposure to diesel exhaust

    PubMed Central

    Laumbach, Robert; Tong, Jian; Zhang, Lin; Ohman-Strickland, Pamela; Stern, Alan; Fiedler, Nancy; Kipen, Howard; Kelly-McNeil, Kathie; Lioy, Paul


    Diesel exhaust (DE) is a significant source of air pollution that has been linked to respiratory and cardiovascular morbidity and mortality. Many components in DE, such as polycyclic aromatic hydrocarbons, are present in the environment from other sources. 1-Nitropyrene appears to be a more specific marker of DE exposure. 1-Nitropyrene is partially metabolized to 1-aminopyrene and excreted in urine. We developed a practical, sensitive method for measuring 1-aminopyrene in human urine using a HPLC-fluorescence technique. We measured 1-aminopyrene concentrations in spot urine samples collected prior to and during 24 h following the start of 1 h controlled exposures to DE (target concentration 300 μg m−3 as PM10) and clean air control. Time-weighted-average concentrations of urinary 1-aminopyrene were significantly greater following the DE exposure compared to the control (median 138.7 ng g−1 creatinine vs. 21.7 ng g−1 creatinine, p < 0.0001). Comparing DE to control exposures, we observed significant increases in 1-aminopyrine concentration from pre-exposure to either first post-exposure void or peak spot urine concentration following exposure (p = 0.027 and p = 0.0026, respectively). Large inter-individual variability, in both the concentration of urinary 1-aminopyrene and the time course of appearance in the urine following the standardized exposure to DE, suggests the need to explore subject variables that may affect conversion of inhaled 1-nitropyrene to urinary excretion of 1-aminopyrene. PMID:19137151

  9. Purification and characterization of a benzene hydroxylase: A cytochrome P-450 from rat liver mitochondria

    SciTech Connect

    Karaszkiewicz, J.W.


    This laboratory previously demonstrated that incubation of ({sup 14}C)benzene with isolated mitochondria resulted in the formation of mtDNA adducts. Since benzene is incapable of spontaneously covalently binding to nuclei acids, it was hypothesized that enzyme(s) present in the organelle metabolized benzene to reactive derivatives. We have purified, to electrophoretic homogeneity, a 52 kDa cytochrome P-450 from liver mitoplasts which metabolizes benzene to phenol. The enzyme has a K{sub M} for benzene of 0.012 mM, and a V{sub MAX} of 22.6 nmol phenol/nmol P-450/10 min, and requires NADPH, adrenodoxin, and adrenodoxin reductase for activity. Activity also can be reconstituted with microsomal cytochrome P-450 reductase. Benzene hydroxylase activity could be inhibited by carbon monoxide and SKF-525A, and by specific inhibitors of microsomal benzene metabolism. The purified enzyme oxidized phenol, forming catechol; aminopyrine N-demethylase activity was also demonstrated. These data confirm that a cytochrome P-450 of mitochondrial origin is involved in benzene metabolism, and indicate a role for the mitochondrion in xenobiotic activation.

  10. Canine gastric mucosal vasodilation with prostaglandins and histamine analogs

    SciTech Connect

    Gerber, J.G.; Nies, A.S.


    The effect of direct intragastric artery infusion of prostaglandins E2 and I2, arachidonic acid, dimaprit (histamine H2 agonist), and 2',2'-pyridylethylamine (histamine H1 agonist) on gastric mucosal blood flow was examined in dogs to elucidate the relationship between gastric secretory state and mucosal blood flow in dogs. These compounds were chosen because of their diverse effect on gastric acid secretion. Gastric fundus blood flow was measured both electromagnetically with a flow probe around the left gastric artery which supplies the fundus almost exclusively, and by the radioactive microsphere technique. Intraarterial infusion of all the compounds resulted in gastric mucosal vasodilation even though PGE2, PGI2, and arachidonic acid inhibit gastric acid secretion, dimaprit stimulated gastric acid secretion, and 2',2'-pyridylethylamine does not affect gastric acid secretion. There was total agreement in the blood flow measurements by the two different techniques. Our data suggest that gastric acid secretion and gastric vasodilation are independently regulated. In addition, the validity of the studies in which the aminopyrine clearance indicates that prostaglandins are mucosal vasoconstrictors needs to be questioned because of the reliance of those measurements on the secretory state of the stomach.

  11. Effects of mammalian CYP3A inducers on CYP3A-related enzyme activities in grass carp (Ctenopharyngodon idellus): Possible implications for the establishment of a fish CYP3A induction model.


    Li, Dan; Yang, Xian-Le; Zhang, Shu-Jun; Lin, Mao; Yu, Wen-Juan; Hu, Kun


    Unexpected drug-drug interactions in fish are generally associated with the induction of CYP3A activity and may lead to the formation of drug residues and thus threaten the safety of fishery products. However, little information is available about CYP3A induction in fish. In the present study, we determined the in vivo and in vitro effects of typical mammalian CYP3A inducers (rifampicin, phenobarbital and dexamethasone) on CYP3A-related enzyme activities in a freshwater teleost, the grass carp (Ctenopharyngodon idellus). Our results showed that the response to rifampicin was similar for grass carp liver cell line (GCL), liver microsomes and the primary hepatocytes of grass carp, as indicated by the activity of aminopyrine N-demethylase (APND). When erythromycin N-demethylase (ERND) and 6beta-testosterone hydroxylase (6beta-TOH) were taken into consideration, the GCL displayed a greater capacity for conducting CYP3A metabolism and induction than the C. idellus kidney cell line (CIK). Using erythromycin and testosterone as substrates, we demonstrated that CYP3A catalysis exhibited non-Michaelis-Menten kinetics in GCL cells, and that V(max)/K(m) values were significantly increased due to rifampicin-treatment. Overall, this study may have implications for the use of GCL as a CYP3A induction model to identify physiological changes in fish as well as the similarities or differences between fish and mammals.

  12. Effect of Esters on the Permeation of Chemicals with Different Polarities through Synthetic Artificial Membranes Using a High-Throughput Diffusion Cell Array.


    Uchida, Takashi; Nishioka, Keisuke; Motoki, Anzu; Yakumaru, Masafumi; Sano, Tomohiko; Todo, Hiroaki; Sugibayashi, Kenji


    This study investigated the effects of 25 kinds of esters that are used in cosmetics on the permeation of four model compounds with different polarities (caffeine [CF], aminopyrine [AMP], benzoic acid [BA], and flurbiprofen [FP]). The amount of each model compound that permeated through two types of artificial membrane (silicone and Strat-M(®)) was measured and correlated with the physicochemical properties of the esters, including their solubility, viscosity, wettability, surface tension, and uptake. The amount of each model compound that permeated through the silicone membrane was not significantly correlated with the solubility of the esters but was significantly correlated with all other measured physical properties of the esters. Similar correlations were observed for the amounts of AMP, BA, and FP that passed through the Strat-M(®) membrane. However, the amount of CF that permeated through the Strat-M(®) membrane also correlated with the solubility of the esters. There was a highly significant correlation between the amount permeating through the silicone and Strat-M(®) membranes because the model compounds had high lipophilicity. These findings demonstrated that to control the permeation of various chemicals through artificial membranes, it is important to consider the uptake of the esters and that the solubility of the esters is also an important consideration when using a more complex membrane.

  13. Xenobiotics in gametes of Lake Michigan lake trout (Salvelinus namaycush) induce hepatic monooxygenase activity in their offspring

    SciTech Connect

    Binder, R.L.; Lech, J.J.


    Eggs spawned from Lake Michigan lake trout contain a number of xenobiotic compounds, including polychlorinated biphenyls (PCBs). To assess whether this contamination is sufficient to induce hepatic cytochrome P-450-dependent monooxygenase (MO) activity during early development, the hepatic MO systems of laboratory-cultured offspring of Lake Michigan, Green Bay, and Marquette Hatchery lake trout were compared. Additionally, the induction of hepatic cytochrome P-450 systems in developing lake trout by the commercial PCB mixture, Aroclor 1254 (A1254), was characterized. During late embryonic development and at the swim-up stage, the hepatic MO systems of the feral lake trout offspring appeared induced, based on levels of aryl hydrocarbon hydroxylase (AHH) activity that were 3.5- to 8.6-fold higher than the hatchery control levels. Furthermore, at the swim-up stage the feral trout offspring resembled A1254-treated hatchery fry with regard to the degree of inhibition of hepatic AHH activity by alpha-naphthoflavone, and the presence of an inducible Mr . 58,000 polypeptide in hepatic microsomes. The levels of aminopyrine N-demethylase activity, which was relatively unresponsive to inducers, were moderately lower in the Lake Michigan and Green Bay swim-up fry compared to the hatchery control levels. After 7 months of posthatching laboratory culture, when residues of xenobiotics present at fertilization were greatly diluted by growth, the hepatic MO systems of the Lake Michigan and hatchery trout offspring appeared essentially indistinguishable with regard to a number of parameters.

  14. Effect of zinc deficiency on NADPH and cytochrome P-450 dependent active oxygen generation in rat lung and liver

    SciTech Connect

    Hammermueller, J.D.; Bray, T.M.; Bettger, W.J.


    The cyt. P-450 system and cyt. P-450 reductase are involved in the generation of active oxygen species such as H/sub 2/O/sub 2/. The objective of this study was to investigate the effect of short term, severe, dietary zinc deficiency in rats on the formation of active oxygen in vitro. Weanling male Wistar rats were fed egg white-based diets containing less than 1 ppm Zn (ZnD). Controls were fed ad libitum (ZnAl) or pair-fed (ZnPF) a diet containing 100 ppm Zn. After 3 weeks lung and liver microsomes were assayed for H/sub 2/O/sub 2/ production (pmol H/sub 2/O/sub 2//mg protein/min) and cyt. P-450 reductase activity (nmol cyt. C reduced/mg protein/min). For the measurement of H/sub 2/O/sub 2/ production exogenous substrate (aminopyrine) and NADPH (cofactor) were provided to drive the cyt. P-450 system and NaN/sub 3/ was used to inhibit catalase. The results showed a significant effect of dietary Zn on NADPH and cyt. P-450 dependent active oxygen generation and support the hypothesis that Zn has a role in the function of biomembranes.

  15. Alteration of drug metabolizing enzymes in sulphite oxidase deficiency

    PubMed Central

    Tutuncu, Begum; Kuçukatay, Vural; Arslan, Sevki; Sahin, Barbaros; Semiz, Asli; Sen, Alaattin


    The aim of this study was to investigate the possible effects of sulphite oxidase (SOX, E.C. deficiency on xenobiotic metabolism. For this purpose, SOX deficiency was produced in rats by the administration of a low molybdenum diet with concurrent addition of 200 ppm tungsten to their drinking water. First, hepatic SOX activity in deficient groups was measured to confirm SOX deficiency. Then, aminopyrine N-demethylase, aniline 4-hydroxylase, aromatase, caffeine N-demethylase, cytochrome b5 reductase, erythromycin N-demethylase, ethoxyresorufin O-deethylase, glutathione S-transferase, N-nitrosodimethylamine N-demethylase and penthoxyresorufin O-deethylase activities were determined to follow changes in the activity of drug metabolizing enzymes in SOX-deficient rats. Our results clearly demonstrated that SOX deficiency significantly elevated A4H, caffeine N-demethylase, erythromycin N-demethylase and N-nitrosodimethylamine N-demethylase activities while decreasing ethoxyresorufin O-deethylase and aromatase activities. These alterations in drug metabolizing enzymes can contribute to the varying susceptibility and response of sulphite-sensitive individuals to different drugs and/or therapeutics used for treatments. PMID:22798713

  16. Prognostic Value of Metabolic Liver Function Tests: a Study on 711 Cirrhotic Patients.


    Lebossé, Fanny; Guillaud, Olivier; Forestier, Julien; Ecochard, Marie; Boillot, Olivier; Roman, Sabine; Mion, François; Dumortier, Jérôme


    The prognosis of cirrhotic patients is usually assessed by Child-Pugh and MELD scores. Metabolic liver function tests such as aminopyrine breath test (ABT) and indocyanine green clearance (IGC) have been shown to reveal hepatocellular dysfunction. The aim of this retrospective study was to compare the prognostic value of the MELD score, Child-Pugh score, ABT and IGC in a large cohort of cirrhotic patients. Between January 1996 and June 2008, 711 cirrhotic patients were included and the primary endpoint was survival without LT. The ROC curves with c-statistics, correlation coefficient and survival were calculated. Metabolic function tests and scores were strongly correlated. At the time of evaluation, 111 patients had died and 520 had received a transplant. Prognostic ability (estimated by the AUROC curve) to predict survival without LT at 6 months was 0.662, 0.691, 0.738 and 0.715 for ABT, IGC, Child-Pugh score and MELD score, respectively. Similarly, at 1 year, AUROC was 0.738 for Child-Pugh score, 0.716 for MELD score, 0.693 for IGC clearance and 0.651 for ABT. Our results strongly confirm that IGC and ABT have a high prognostic value in cirrhotic patients, similar to Child-Pugh and MELD scores. They could be developed to routinely evaluate the prognosis of patients in addition to clinical and biochemical data.

  17. Antinociceptive and Anti-Inflammatory Effects of Ethanolic Extracts of Glycine max (L.) Merr and Rhynchosia nulubilis Seeds

    PubMed Central

    Yim, Joo Hyuk; Lee, Ok-Hwan; Choi, Ung-Kyu; Kim, Young-Chan


    The aim of this study was to assess the in vivo potential of ethanolic extracts of Glycine max (L.) Merr. (SoRiTae) and Rhynchosia nulubilis (Yak-Kong) seeds as natural anti-nociceptive and anti-inflammatory agents. To assess the anti-nociceptive and anti-inflammatory potential, the ethanolic extracts of SoRiTae and Yak-Kong seeds were tested in arachidonic acid-induced ear edema, carrageenan induced paw edema, formalin-induced licking time, acetic acid induced writhing and hot plate-induced thermal stimulation in mice. The administration of ethanolic extracts of SoRiTae and Yak-Kong seeds evoked a significant effect of anti-nociceptive and anti-inflammatory activities as compared to standards aminopyrine and indomethacin. The ear edema, paw edema, paw licking time, pain and writhes in mice were significantly reduced (p < 0.05) as compared to the control. The results obtained in this study indicate that both SoRiTae and Yak-Kong soybeans possesses potential anti-nociceptive and anti-inflammatory activities. PMID:20087462

  18. [Breath-analysis tests in gastroenetrological diagnosis].


    Caspary, W F


    The introduction of a simple method for analysis of 14CO2 in breath allowed a more widely application of breath-tests in the diagnosis of gastroenterological diseases. During a breath-test a 14C-labelled compound is administered orally and 14CO2 is subsequently measured in breath by discontinuous samplings of 14CO2 by virtue of a trapping solution (hyamine hydroxide). Most helpful tests in gastroenterology are the 14C-glycyl-cholate breath test for detecting increased deconjugation of bile acids due to small intestinal bacterial overgrowth or bile acid malabsorption in ileal resection or Crohn's disease of the ileum, the 14C-lactose breath test in lactase deficiency, whereas the 14C-tripalmitin test seems less helpful in the diagnosis of fat malabsorption. A 14C-aminopyrine breath test may turn out to be a simple and valuable liver function test. Oral loading tests with breath analysis of H2 have shown to be helpful in the diagnosis of carbohydrate malabsorption, determination of intestinal transit time and intestinal gas production. Due to technical reasons (gas-chromatographie analysis) H2-breath analysis is still limited to research centers. Despite low radiation doses after oral administration of 14C-labelled compounds oral loading tests with H2- or 13C-analysis might be preferable in the future.

  19. Analgesic and anti-inflammatory activities of Polygonum stagninum.


    Mazid, M Abdul; Datta, Bidyut K; Bachar, Sitesh C; Bashar, S A M Khairul; Nahar, Lutfun; Sarker, Satyajit D


    The n-hexane, ethyl acetate (EtOAc), and methanol extracts of the aerial parts of Polygonum stagninum Buch.-Ham. ex Meissn. (Polygonaceae), a Bangladeshi medicinal plant, were assessed for analgesic and anti-inflammatory properties in experimental mice and/or rat models. In the acetic-acid-induced writhing test in mice, all extracts displayed a dose dependent analgesic effect. The most potent analgesic activity was observed with the EtOAc extract at the dose of 400 mg/kg body weight, with an inhibition of writhing response of 50.3% compared to 62.2% for the positive control aminopyrine. Among the extracts, n-hexane extract at the doses of 200 and 400 mg/kg body weight showed the highest levels of anti-inflammatory activity after 2 h, with the inhibition of paw edema of 60.1% and 64.1%, respectively, and this effect was much better than that of the conventional anti-inflammatory agent phenylbutazone (maximum inhibition of 38.3% after 4 h).

  20. Ultra-fast LC-ESI-MS/MS method for the simultaneous determination of six highly toxic Aconitum alkaloids from Aconiti kusnezoffii radix in rat plasma and its application to a pharmacokinetic study.


    Liu, Jingjing; Li, Qing; Yin, Yidi; Liu, Ran; Xu, Huarong; Bi, Kaishun


    A fast, sensitive, and efficient ultra-fast LC-ESI-MS/MS method was developed for the simultaneous quantitation of six highly toxic Aconitum alkaloids, that is, aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, in rat plasma after oral administration of crude ethanol extracts from Aconiti kusnezoffii radix by ultrasonic extraction, reflux extraction for 1 h, and reflux extraction for 3 h, respectively. The separation of six Aconitum alkaloids and aminopyrine (internal standard) was performed on an InertSustain® C18 column, and the quantification of the analytes was performed on a 4000Q ultra-fast LC-MS/MS system with turbo ion spray source in the positive ion and multiple-reaction monitoring mode. Absolute recoveries ranged within 65.06-85.1% for plasma samples. The intra- and interday precision and accuracy of analytes were satisfactory. The methods were validated with sensitivity reaching the lower LOQ for aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, which were 0.025, 0.025, 0.050, 0.025, 0.025, and 0.100 ng/mL, respectively. The method was successfully applied to a pharmacokinetic study of six Aconitum alkaloids in rat plasma after oral administration of crude ethanol extracts from the raw root of Aconitum kusnezoffii Reichb. by three different extraction processes.

  1. Biotransformation of malachite green by Saccharomyces cerevisiae MTCC 463.


    Jadhav, J P; Govindwar, S P


    In recent years, use of microbial biomass for decolourization of textile industry wastewater is becoming a promising alternative in which some bacteria and fungi are used to replace present treatment processes. Saccharomyces cerevisiae MTCC 463 decolourized the triphenylmethane dyes (malachite green, cotton blue, methyl violet and crystal violet) by biosorption, showing different decolourization patterns. However, malachite green decolourized by biosorption at the initial stage and further biodegradation occurred, about 85% in plain distilled water within 7 h, and about 95.5% in 5% glucose medium within 4 h, under aerobic conditions and at room temperature. Decolourization of malachite green depends on various conditions, such as concentration of dye, concentration of cells, composition of medium and agitation. HPLC, UV-VIS, FTIR and TLC analysis of samples extracted with ethyl acetate from decolourized culture flasks confirmed the biodegradation of malachite green into several metabolites. A study of the enzymes responsible for the biodegradation of malachite green in the control and cells obtained after decolourization showed the activities of laccase, lignin peroxidase, NADH-DCIP reductase, malachite green reductase and aminopyrine N-demethylase in control cells. A significant increase in the activities of NADH-DCIP reductase and MG reductase was observed in the cells obtained after decolourization, indicating a major involvement of reductases in malachite green degradation.

  2. Effect of 13-NLE-motilin on gastric secretion, serum gastrin level and mucosal blood flow in dogs.

    PubMed Central

    Konturek, S J; Dembinski, A; Krol, R; Wünsch, E


    1. In dogs with gastric fistulas and vagally innervated fundic and antral pouches, 13-norleucine-motilin (13-nle-motilin), a synthetic analogue of motilin, infused intravenously in graded doses produced a dose-dependent increase in gastric acid and pepsin outputs. 2. The motilin-induced stimulation of gastric secretion occurred independently of antral pH and was not accompanied by any alteration in the serum gastrin level suggesting that motilin did not affect the release of gastrin. 3. When infused intravenously in a constant dose against a constant background stimulation with pentagastrin or histamine 13-nle-motilin inhibited both acid and pepsin secretion from the main stomach and fundic pouch. 4. The inhibitory effect of 13-nle-motilin was always associated with a marked reduction in mucosal blood flow but without any change in the ratio of aminopyrine concentration in the gastric juice and blood plasma indicating that this peptide primarily affected gastric secretion but did not limit the gastric mucosal microcirculation. PMID:321755

  3. Inhibition of acid formation by epidermal growth factor in the isolated rabbit gastric glands.

    PubMed Central

    Dembiński, A; Drozdowicz, D; Gregory, H; Konturek, S J; Warzecha, Z


    The effects of epidermal growth factor (EGF) on basal and stimulated (with histamine, dibutyryl cyclic AMP, and high concentrations of K+) acid formation have been studied in isolated glands from the rabbit gastric mucosa. The changes in the accumulation of [14C]aminopyrine [14C]AP have been used as an indirect measurement of acid production in the glands. Unstimulated gastric glands accumulated [14C]AP indicating the existence of basal acid production in these glands, and EGF caused a small but significant reduction in basal [14C]AP uptake. A similar reduction of basal [14C]AP uptake was observed after exposure to omeprazole but not after ranitidine or prostaglandin E2 (PGE2). Histamine, dibutyryl cyclic AMP and K+ caused a strong and dose-dependent stimulation of acid formation by the glands. EGF, like omeprazole, reduced dose-dependently the [14C]AP accumulation stimulated by both histamine and dibutyryl cyclic AMP, while ranitidine and PGE2 reduced histamine- but not dibutyryl-cyclic-AMP-stimulated accumulation of [14C]AP. In the absence of other external stimuli, an increased K+ concentration enhanced [14C]AP accumulation to levels similar to those produced by histamine and this effect was not changed by EGF, ranitidine or PGE2 but was inhibited by omeprazole. We conclude that EGF interferes with the final steps of acid production between cyclic nucleotides and proton pump of the parietal cells. PMID:3025433

  4. Structural modification of H/sub 2/-receptor antagonists provide post-H/sub 2/-receptor gastric antisecretory activity

    SciTech Connect

    Nielsen, S.T.; Dove, P.A.; Strike, D.P.; Schiehser, G.A.


    In the course of investigations into the gastric antisecretory activity of potential H/sub 2/-receptor antagonists, examples were discovered in which structural modification of the molecule altered a) antisecretory activity in the pylorus-ligated rat and b) the response to various stimulants of (/sup 14/C)aminopyrine (AP) uptake in isolated rat gastric mucosal cell preparations. Wy-45,662 (N-(3-(3-(1-piperidinylmethyl)phenoxy)propyl)thieno(3,4-d) isothiazol-3-amine 1, 1-dioxide)), a very potent histamine H/sub 2/-antagonist and antisecretory agent in the rat (ED/sub 50/ (approx.) 0.3 mg/kg), had no effect in vitro at 1 on forskolin-induced (/sup 14/C)AP uptake while 10 nM Wy-45,662 completely suppressed histamine-stimulated (/sup 14/C)AP uptake. In contrast, the N-benzylated form of Wy-45,662, Wy-46,499 dose-dependently (10/sup -7/-10/sup -6/M) suppressed forskolin-stimulated (/sup 14/C)AP uptake while retaining modest antisecretory activity (ED/sub 50/approx.8 mg/kg) in vivo. Wy-46,499's modest antisecretory activity was thus attributable to inhibition via a post-histamine H/sub 2/-receptor mechanism.

  5. Effect of amphetamine on the hepatic endoplasmic reticulum of the pregnant rat.


    Feuer, G; de la Iglesia, F


    Search for the elucidation of the mode of action of amphetamines has revealed that this drug brought about changes in the activity of some enzymes bound to the hepatic endoplasmic reticulum of the pregnant and non-pregnant rat. Amphetamine administration caused loss of appetite and changes in enzyme activity due to starvation, however, its effects were assessed applying pair-feeding conditions. Drug-metabolizing activity was increased by amphetamine as measured by coumarin 3-hydroxylase and aminopyrine N-demethylase in both pregnant and non-pregnant animals; aniline hydroxylase was elevated only in pregnant rats. These changes were associated with the enhanced synthesis of microsomal phospholipids as indicated by the increased activity of [14C-Me]S-adenosyl-L-methionine : microsomal phospholipid methyl transferase, de novo synthesis and levels of microsomal phospholipids. These effects were mainly manifest in phosphatidylethanolamine and phosphatidylcholine fractions. Glucose-6-phosphatase activity remained unaltered by amphetamine. Pregnancy alone brought about a reduction of all these microsomal parameters. The rise of hepatic drug metabolism following the administration of amphetamine indicated a compensatory mechanism by means of stimulating enzyme induction processes.

  6. Effect of penicillin-based antibiotics, amoxicillin, ampicillin, and piperacillin, on drug-metabolizing activities of human hepatic cytochromes P450.


    Niwa, Toshiro; Morimoto, Mari; Hirai, Takako; Hata, Tomomi; Hayashi, Misato; Imagawa, Yurie


    The effects of three kinds of penicillin-based antibiotics, amoxicillin, ampicillin, and piperacillin, on drug-metabolizing activity of human hepatic cytochrome P450 (P450 or CYP) were investigated. Metabolic activities of P450s expressed in recombinant Escherichia coli at substrate concentrations around the Michaelis constant were compared in the presence or absence of the antibiotics. Amoxicillin, ampicillin, and piperacillin at 0.5 or 1 mM concentrations neither inhibited nor stimulated CYP2C9-mediated tolbutamide methylhydroxylation, CYP2D6-mediated dopamine formation from p-tyramine, or CYP3A4- or CYP3A5-mediated testosterone 6β-hydroxylation. However, amoxicillin and piperacillin inhibited CYP2C8-mediated aminopyrine N-demethylation at 50% inhibitory concentration of 0.83 and 1.14 mM, respectively. These results suggest that piperacillin might inhibit CYP2C8 clinically, although the interactions between these three penicillin-based antibiotics and other drugs that are metabolized by P450s investigated would not be clinically significant.

  7. Inhibitions of acid secretion by E3810 and omeprazole, and their reversal by glutathione.


    Fujisaki, H; Shibata, H; Oketani, K; Murakami, M; Fujimoto, M; Wakabayashi, T; Yamatsu, I; Yamaguchi, M; Sakai, H; Takeguchi, N


    A substituted benzimidazole ([4-(3-methoxypropoxy)-3-methylpyridine-2-yl]methylsulfinyl)- 1H-benzimidazole sodium salt (E3810), is a gastric proton pump (H+, K(+)-ATPase) inhibitor. E3810 and omeprazole inhibited acid accumulation dose dependently as measured with aminopyrine uptake in isolated rabbit gastric glands, their IC50 values being 0.16 and 0.36 microM, respectively. The addition of exogenous reduced glutathione (GSH) to the gland suspension reactivated dose dependently the acid secretion which had been inhibited by 2 microM E3810 or omeprazole as a function of the incubation time. Furthermore, GSH at 1 and 3 mM reversed the antisecretory effect of E3810 more quickly than it did that of omeprazole. The antisecretory effect of E3810 was slightly greater than that of omeprazole in histamine-stimulated fistula dogs in vivo. The duration of the antisecretory activity of E3810 at concentrations of 2 and 4 mg/kg was shorter than that of omeprazole at the same concentrations in pentagastrin-stimulated fistula dogs. The reversal of the antisecretory activity of the inhibitors in dogs is suggested to be due to the action of endogenous extracellular GSH, in addition to de novo synthesis of the proton pump, because bullfrog gastric mucosae were found in the present study to secrete GSH into the mucosal solution at the rate of about 0.25 nmol/min/g tissue.

  8. [Inhibitory action of E3810 on H+,K(+)-ATPase and gastric acid secretion in vitro].


    Fujisaki, H; Oketani, K; Shibata, H; Murakami, M; Fujimoto, M; Wakabayashi, T; Yamatsu, I; Takeguchi, N


    The inhibitory action of (+-)-sodium 2-[(4-(3-methoxypropoxy)-3-methylpyridine-2-yl) methylsulfinyl]-1H- benzimidazole (E3810) on H+,K(+)-ATPase and gastric acid secretion in vitro was investigated, and it was compared with those of omeprazole (OPZ). E3810 concentration-dependently inhibited the H+,K(+)-ATPase activity of hog gastric vesicles. Its IC50 was 0.26 microM at pH 6.1. The inhibition was irreversible in nature and reversed by dithiothreitol. The potency of E3810 was 10-times that of omeprazole. Acidification of the intravesicular (luminal) space increased 1000-fold the potency of E3810, indicating that E3810 is a specific inhibitor which binds to the luminal cysteine residue of H+,K(+)-ATPase. Prolonged incubation of up to 180 min in the absence of thiol reagents of rabbit gastric glands which had been inhibited by a low concentration of E3810 (0.3 and 0.5 microM) time-dependently and completely reversed the inhibition, as determined by aminopyrine uptake, whereas it did not recover the acid secretion in omeprazole-treated glands. These results suggest that the acid-activated E3810 is a potent specific inhibitor of H+,K(+)-ATPase, and that the duration of the inhibitory action of E3810 is much shorter than that of omeprazole in isolated gastric glands.

  9. [Growth in children with diabetes insipidus].


    Morla Báez, E; Dorantes Alvarez, L M; Chavarría Bonequi, C


    Commercial preparations of vasopressin for the treatment of diabetes insipidus are not available in Mexico. Besides, the hormone is useless in the nephrogenic variety. In the department of Endocrinology at the Hospital Infantil de Mexico, a preparation containing hydrochlorothiazide, aminopyrine and potassium chloride, which reduces urinary volumes in about two thirds, is employed in all varieties of the disease. Growth in stature was investigated in 44 patients under treatment, attending the Endocrine Outpatient Clinic since 1967 for a period of 2 to 12 years. Clinical material included 29 males and 15 females. There were 23 idiopathic, 7 histiocytosis, 5 nephrogenic, 4 craniopharyngiomas, 2 psychogenic polydipsia, 2 traumatic and 1, as a sequel of tuberculous meningoencephalitis. Six idiopathic, 2 nephrogenic, 2 traumatic, 1 histiocytosis, and 1 psychogenic proceeded between percentiles 3 and 97, parallel to the nearest line of reference along the whole period of study. Two nephrogenic, 2 histiocytosis, 1 psychogenic, 1 post-meningoencephalitis and 14 idiopathic, grew below the third percentile, but parallel to it. One nephrogenic, 4 histiocytosis, 4 craniopharyngioma and 3 idiopathic progressively departed from the initial centile. Two of the latter had growth hormone deficiency, and 1 had been very irregularly treated. It is concluded that the therapy employed limits stature impairment but does not produce catch-up growth. Accordingly, it is proposed that the treatment of diabetes insipidus should be started as early as possible, and that if progress in stature is appreciably deteriorated, the presence of additional pathology should be suspected.

  10. Biodegradation of reactive textile dye Red BLI by an isolated bacterium Pseudomonas sp. SUK1.


    Kalyani, D C; Patil, P S; Jadhav, J P; Govindwar, S P


    A novel bacterial strain capable of decolorizing reactive textile dye Red BLI is isolated from the soil sample collected from contaminated sites of textile industry from Solapur, India. The bacterial isolate was identified as Pseudomonas sp. SUK1 on the basis of 16S rDNA analysis. The Pseudomonas sp. SUK1 decolorized Red BLI (50 mg l(-1)) 99.28% within 1h under static anoxic condition at pH range from 6.5 to 7.0 and 30 degrees C. This strain has ability to decolorize various reactive textile dyes. UV-Vis spectroscopy, FTIR and TLC analysis of samples before and after dye decolorization in culture medium confirmed decolorization of Red BLI. A significant increase in the activities of aminopyrine N-demethylase and NADH-DCIP reductase in cells obtained after decolorization indicates involvement of these enzymes in the decolorization process. Phytotoxicity testing with the seeds of Sorghum vulgare and Phaseolus mungo, showed more sensitivity towards the dye, while the products obtained after dye decolorization does not have any inhibitory effects.

  11. Brevibacillus laterosporus MTCC 2298: a potential azo dye degrader.


    Gomare, S S; Govindwar, S P


    To evaluate the potential of Brevibacillus laterosporus MTCC 2298 for the decolourization of different textile azo dyes including methyl red, mechanism of biotransformation and the toxicity of products. Brevibacillus laterosporus showed decolourization of thirteen different azo dyes including methyl red. Decolourization of methyl red was faster (93% within 12 h) under static condition at the concentration 0.2 g l(-1). Induction in the activities of lignin peroxidase, laccase, aminopyrine N-demethylase, NADH-DCIP reductase and malachite green reductase was observed in the cells obtained after decolourization. Fourier transform infra-red spectral analysis of products indicated conversion of methyl red into secondary aryl amines and nitrosamines, which further transformed into the aromatic nitro compounds. Gas chromatography-mass spectroscopy analysis suggested conversion of methyl red into high molecular weight complex derivatives. The heterocyclic substituted aryl amine (m/z 281), p-(N,N di formyl)-substituted para-di amino benzene derivative (m/z 355) and p-di-amino benzene derivative (m/z 282) are the mainly elected biotransformation products. Microbial and phytotoxicity studies suggested nontoxic nature of the biotransformation products. Brevibacillus laterosporus has potential for the decolourization of different textile azo dyes. Brevibacillus laterosporus decolourized different azo dyes including methyl red and can be utilized for textile dye decolourization.

  12. Subchronic toxicity of 2,2{prime},3,3{prime},4,4{prime}-hexachlorobiphenyl in rats

    SciTech Connect

    Lecavalier, P.; Chu, I.; Feeley, M.


    The subchronic toxicity of 2,2{prime},3,3{prime},4,4{prime}-hexachlorobiphenyl (PCB 128) was investigated in rats following dietary exposure at 0, 0.05, 0.5, 5, or 50 ppm for 13 wk. The growth rate was not affected by treatment and no apparent clinical signs of toxicity were observed. There was a significant increase in liver weight in the 50 ppm females. The liver ethoxy-resorufin deethylase (EROD) activity was increased by five- and fourfold in the highest dose males and females, respectively, while aminopyrine demethylase (ADPM) activity was significantly increased only in the highest dose females. Liver vitamin A was significantly reduced in the highest dose females. No other biochemical or hematological effects were observed. Treatment-related histopathological changes were seen in the thyroid and liver, and to a lesser extent in the bone marrow and thymus. Residue data showed a dose-dependent accumulation of PCB 128 in the following tissues: fat, liver, kidney, brain, spleen, and serum, with the highest concentration being found in fat followed by liver and kidney. Based on these data, the no-observable-adverse-effect level of PCB 128 was judged to be 0.5 ppm in diet or 42 {mu}g/kg body weight. 29 refs., 1 fig., 5 tabs.

  13. Long-term toxicity of octachlorostyrene in the rat

    SciTech Connect

    Chu, I.; Villeneuve, D.C.; Secours, V.E.; Valli, V.E.; Leeson, S.; Shen, S.Y.


    This study was designed to investigate the toxic effects produced by the long-term exposure to octachlorostyrene (OCS), a demonstrated environmental contaminant in the Great Lakes region of North America and the Norwegian Coast in Europe. Groups of 20 male and 20 female rats were administered OCS in diets at 0.005, 0.05, 0.5, 5.0, or 50 ppm for 12 months. Weight gain and food consumption were not affected. Increased liver weights were observed in the groups fed the highest dose of OCS. Hepatic microsomal aniline hydroxylase and aminopyrine demethylase activities were induced in male rats fed 5.0 ppm OCS and higher and in female rats fed 50 ppm of the chemical. Elevated serum cholesterol levels were seen in rats of both sexes fed the highest dose. Treatment-related histological changes occurred in the thyroid, liver, and kidney of rats. A dose-dependent accumulation of OCS in the fat and liver of the rats was found. Based on the data presented, it was concluded that the no adverse effect level of OCS was 0.5 ppm.

  14. Studies on the mechanism of paracetamol-induced protection against paracetamol hepatotoxicity.


    Strubelt, O; Siegers, C P; Völpel, M; Younes, M


    In rats, 3 days treatment with paracetamol (1 oral dose of 1 g/kg daily) produced a complete protection against the hepatotoxic actions of a further dose of paracetamol as documented by determination of serum enzyme activities (glutamic-oxaloacetic transaminase, (GOT), glutamic-pyruvic transaminase (GPT), sorbitol dehydrogenase (SDH), bromsulphthalein retention and histological investigations. Subacute paracetamol treatment decreased liver glutathione levels by 46%, liver microsomal cytochrome P-450 content by 23%, hepatic hydroxylation of aniline by 29% and hepatic demethylation of aminopyrine by 46%. It afforded also some protection against the hepatotoxic actions of carbon tetrachloride, bromobenzene and thioacetamide, but did not influence the antiphlogistic activity of paracetamol (carrageenan paw edema test). Plasma and liver concentrations of free paracetamol after oral administration of 1 g/kg paracetamol were somewhat higher in the subacutely paracetamol-pretreated rats than in the non-pretreated control animals whereas no differences in the concentrations of conjugated paracetamol were found between the 2 groups. Pretreatment with paracetamol did not influence the urinary excretion of free paracetamol but caused some shift in the urinary excretion of paracetamol conjugates: pretreated rats excreted 23% less of the paracetamol glucuronide and sulfate and 33% more of the paracetamol mercapturate than the control animals. A depression of the microsomal mixed-function oxidase activity is presumed to be the main cause of the paracetamol-induced protection against paracetamol hepatotoxicity.

  15. Induction and inhibition of cytochrome P450 and drug-metabolizing enzymes by climbazole.


    Kobayashi, Yasuna; Suzuki, Michiya; Ohshiro, Naomi; Sunagawa, Takashi; Sasaki, Tadanori; Oguro, Takiko; Tokuyama, Shogo; Yamamoto, Toshinori; Yoshida, Takemi


    To determine the effect of climbazole on hepatic microsomal cytochrome P450 (P450) and drug-metabolizing enzymes, four different P450 isoforms (CYP2B1, 3A2, 2E1, and 2C12) were examined in female Long-Evans rats. Treatment of rats with climbazole resulted in the induction of P450 content. Climbazole both induced and inhibited aminopyrine N-demethylase activity, but not erythromycin N-demethylase activity. Uridine 5'-phosphate (UDP)-glucuronosyl transferase and glutathione S-transferase activities were also increased with climbazole treatment. Immunoblot analyses revealed that climbazole induces CYP2B1 and CYP3A2 at the lower dose examined, but it failed to increase CYP2B1 at the higher dose. Northern blot analysis revealed that climbazole markedly increases P450 2B1 mRNA. These results indicate that climbazole induces and inhibits P450-dependent drug-metabolizing enzymes in vivo and may have the dose-differential effect on CYP2B1 in rat liver.

  16. Biodegradation of triphenylmethane dye cotton blue by Penicillium ochrochloron MTCC 517.


    Shedbalkar, Utkarsha; Dhanve, Rhishikesh; Jadhav, Jyoti


    Triphenylmethane dyes belong to the most important group of synthetic colorants and are used extensively in the textile industries for dying cotton, wool, silk, nylon, etc. They are generally considered as the xenobiotic compounds, which are very recalcitrant to biodegradation. Penicillium ochrochloron decolorizes cotton blue (50 mg l(-1)) within 2.5 h under static condition at pH 6.5 and temperature 25 degrees C. TLC, FTIR and HPLC analysis confirms biodegradation of cotton blue. FTIR spectroscopy and GC-MS analysis indicated sulphonamide and triphenylmethane as the final products of cotton blue degradation. The pH, temperature and maturity of biomass affected the rate of decolorization. Presence of lignin peroxidase, tyrosinase and aminopyrine N-demethylase activities in the cell homogenate as well as increase in the extracellular activity of lignin peroxidase suggests the role of these enzymes in the decolorization process. The phytotoxicity and microbial toxicity studies of extracted metabolites suggest the less toxic nature of them.

  17. Studies on the mechanism of the acute and carcinogenic effects of N-nitrosodimethylamine on mink liver

    SciTech Connect

    Martino, P.E.; Diaz Gomez, M.I.; Tamayo, D.; Lopez, A.J.; Castro, J.A.


    Outbreaks of liver necrosis and liver hemangiosarcoma were detected in a mink breeding colony in Argentina. Analysis of the Minks' food revealed the presence of 2.6 ppm dimethylnitrosamine (NDMA) in it, apparently as a result of the addition of nitrite as preservative. Previous studies gave evidence of the particular susceptibility of minks to NDMA and other hepatic insults. The authors have determined several biochemical parameters known to correlate with NDMA hepatotoxic effects and compared with them those in rat liver. NDMA administration to both species resulted in the formation of reactive metabolites able to interact with liver DNA to give N/sup 7/-methylguanine and O/sup 6/-methylguanine adducts. Biotransformation of NDMA by liver slices to CO/sub 2/ was significantly lower in the mink than in the rat, whereas the covalent binding (CB) to nucleic acids was slightly lower than in the rat. Aminopyrine N-demethylase activity was also significantly less in mink than in rat liver. The CB of NDMA reactive metabolites to microsomal proteins was not significantly lower in mink as compared to the rat, and the same holds true for the biotransformation of NDMA to formaldehyde by microsomal preparations. Results suggest that the high susceptibility of minks to NDMA might be partially due to a decreased ability to detoxicate NDMA but also a higher intrinsic susceptibility of their liver cells to a given chemical insult.

  18. Purification of the pyrazole-inducible cytochrome P-450 isozyme

    SciTech Connect

    Palakodety, R.; Clejan, L.; Krikun, G.; Feierman, D.; Cederbaum, A.I.


    The alcohol dehydrogenase inhibitor, pyrazole, appears to induce a cytochrome P-450 isozyme with properties similar to the ethanol-inducible P-450. The pyrazole-inducible P-450 isozyme was purified from the liver microsomes of rats treated with pyrazole essentially by the procedure of Ryan et al and also by chromatofocussing. The final preparation appeared homogenous by SDS-PAGE with an apparent molecular weight of 52,000, had a specific content of 11 nmoles P-450 per mg protein, showed very high activity of low K/sub m/ dimethylnitrosamine demethylase and produced a type II binding spectrum with dimethylsulfoxide. The enzyme was also active with aniline and aminopyrine as substrates. Pyrazole itself served as an excellent substrate with 4-hydroxy pyrazole being the product. An antibody against the pyrazole-inducible P-450 raised in chickens recognized a protein with mol.wt of about 52,000 in control microsomes. This band was highly enriched in microsomes from rats treated with pyrazole, 4-methyl-pyrazole, ethanol or acetone, but not phenobarbital or 3-methylcholanthrene. In summary, the pyrazole-inducible P-450 has been purified and appears to be identical in its catalytic and immunological properties to the alcohol-inducible P-450.

  19. Studies on the mechanism of the acute and carcinogenic effects of N-nitrosodimethylamine on mink liver.


    Martino, P E; Diaz Gomez, M I; Tamayo, D; Lopez, A J; Castro, J A


    Outbreaks of liver necrosis and liver hemangiosarcoma were detected in a mink breeding colony in Argentina. Analysis of the Minks' food revealed the presence of 2.6 ppm dimethylnitrosamine (NDMA) in it, apparently as a result of the addition of nitrite as preservative. Previous studies gave evidence of the particular susceptibility of minks to NDMA and other hepatic insults. We have determined several biochemical parameters known to correlate with NDMA hepatotoxic effects and compared them with those in rat liver. NDMA administration to both species resulted in the formation of reactive metabolites able to interact with liver DNA to give N7-methylguanine and O6-methylguanine adducts. Biotransformation of NDMA by liver slices to CO2 was significantly lower in the mink than in the rat, whereas the covalent binding (CB) to nucleic acids was slightly lower than in in the rat. Aminopyrine N-demethylase activity was also significantly less in mink than in rat liver. The CB of NDMA reactive metabolites to microsomal proteins was not significantly lower in mink as compared to the rat, and the same holds true for the biotransformation of NDMA to formaldehyde by microsomal preparations. Results suggest that the high susceptibility of minks to NDMA might be partially due to a decreased ability to detoxicate NDMA but also to a higher intrinsic susceptibility of their liver cells to a given chemical insult.

  20. The formation, disposition, and hepatic metabolism of dimethylnitrosamine in the pig.


    Harrington, G W; Magee, P N; Pylypiw, H M; Kozeniauskas, R; Bevill, R F; Nelson, D R; Thurmon, J C


    The disposition, metabolism, and endogenous formation of N-nitrosodimethylamine (NDMA) from nitrosatable precursors was studied in the intact pig and in animals with cannulated hepatic and portal veins and catheterized bile ducts. Rates of disappearance of NDMA from peripheral venous and arterial blood after iv injections were virtually identical and the compound appeared in bile after a lag time of about 1 hr, with a subsequent decline in biliary concentration at about the same rate as in circulating blood. Measurements of NDMA in portal and hepatic vein blood after oral doses of 10, 1.0 and 0.1 mg/kg, respectively, showed progressively greater hepatic extraction with levels in the hepatic vein approaching the limits of detection after the lowest dose. Both halothane and ethanol virtually abolished the hepatic extraction of NDMA, presumably due to their known inhibitory action on its metabolism in the liver. Endogenous formation of NDMA and N-nitrosomorpholine after oral doses of the amines plus nitrite was demonstrated by their detection and measurement in the portal vein blood. Morpholine was nitrosated more effectively than dimethylamine and inhibited the nitrosation of the latter when the two amines were given together. NDMA was found in the portal blood after sequential oral administration of aminopyrine and nitrite, the concentration being considerably greater after fasting for 24 hr than after a 2-hr fast when much food was present in the stomach.

  1. Effects of ursodeoxycholic acid treatment on nutrition and liver function in patients with cystic fibrosis and longstanding cholestasis.

    PubMed Central

    Cotting, J; Lentze, M J; Reichen, J


    The prevalence of biliary and hepatic diseases is increasing in patients with cystic fibrosis as more of them reach adult life. There is no effective treatment or method of preventing cholestasis in cystic fibrosis, although beneficial effects have been ascribed to the tertiary bile acid, ursodeoxycholate, in other forms of chronic cholestasis. We evaluated prospectively the effects of a six month course of ursodeoxycholate (15-20 mg/kg per day) in eight, mostly adult, patients with cystic fibrosis and chronic cholestasis. Bile acid treatment improved inflammatory activity (average decrease in alanine aminotransferase, 60%, p less than 0.005) and cholestasis (alkaline phosphatase, 47%; p less than 0.01) in all patients. Quantitative liver function, measured by 45 minute sulphobromophthalein retention and by the 14C-aminopyrine breath test, improved in all patients while galactose elimination capacity showed a slight decrease. Patients' nutritional state improved as evidenced by a 1.8 kg weight gain and an increase in muscle mass suggested by a 26% increase in 24 hour urinary creatinine excretion. Steatorrhea was not affected by bile acid treatment. Ursodeoxycholic acid may be beneficial in the treatment of chronic cholestasis in cystic fibrosis by improving liver function and also the patient's nutritional state. PMID:2387518

  2. Effects of ursodeoxycholic acid treatment on nutrition and liver function in patients with cystic fibrosis and longstanding cholestasis.


    Cotting, J; Lentze, M J; Reichen, J


    The prevalence of biliary and hepatic diseases is increasing in patients with cystic fibrosis as more of them reach adult life. There is no effective treatment or method of preventing cholestasis in cystic fibrosis, although beneficial effects have been ascribed to the tertiary bile acid, ursodeoxycholate, in other forms of chronic cholestasis. We evaluated prospectively the effects of a six month course of ursodeoxycholate (15-20 mg/kg per day) in eight, mostly adult, patients with cystic fibrosis and chronic cholestasis. Bile acid treatment improved inflammatory activity (average decrease in alanine aminotransferase, 60%, p less than 0.005) and cholestasis (alkaline phosphatase, 47%; p less than 0.01) in all patients. Quantitative liver function, measured by 45 minute sulphobromophthalein retention and by the 14C-aminopyrine breath test, improved in all patients while galactose elimination capacity showed a slight decrease. Patients' nutritional state improved as evidenced by a 1.8 kg weight gain and an increase in muscle mass suggested by a 26% increase in 24 hour urinary creatinine excretion. Steatorrhea was not affected by bile acid treatment. Ursodeoxycholic acid may be beneficial in the treatment of chronic cholestasis in cystic fibrosis by improving liver function and also the patient's nutritional state.

  3. Determinants of hepatic function in liver cirrhosis in the rat. Multivariate analysis.

    PubMed Central

    Reichen, J; Egger, B; Ohara, N; Zeltner, T B; Zysset, T; Zimmermann, A


    We investigated the determinants of hepatic clearance functions in a rat model of liver cirrhosis induced by phenobarbital/CCl4. Aminopyrine N-demethylation (ABT), galactose elimination (GBT), and serum bile acids (SBA) were determined in vivo. The livers were then characterized hemodynamically: intrahepatic shunting (IHS) was determined by microspheres and sinusoidal capillarization by measuring the extravascular albumin space (EVA) by a multiple indicator dilution technique. The intrinsic clearance was determined by assaying the activity of the rate-limiting enzymes in vitro. Hepatocellular volume (HCV) was measured by morphometry. ABT and SBA, but not GBT, differentiated cirrhotic from normal liver. IHS ranged from normal to 10%; all cirrhotic livers showed evidence of sinusoidal capillarization (reduced EVA). The cirrhotic livers showed a bimodal distribution of HCV, HCV being decreased in 50% of the cirrhotic livers. Multivariate analysis showed EVA and portal flow to be the main determinants of microsomal (ABT) and cytosolic (GBT) clearance function; SBA, by contrast, were determined solely by IHS. We conclude that sinusoidal capillarization is the main determinant of hepatic clearance, while serum bile acids reflect intrahepatic shunting. These findings emphasize the importance of alterations of hepatic nutritional flow to explain reduced clearance function in cirrhosis of the liver. PMID:3198765

  4. Albendazole treatment of echinococcosis in humans: effects on microsomal metabolism and drug tolerance.


    Steiger, U; Cotting, J; Reichen, J


    We prospectively studied the effect of albendazole on microsomal reserve and on first-pass activation to albendazole sulfoxide in patients with hydatid disease. An aminopyrine breath test was performed in 12 patients while they were receiving albendazole treatment and while they were not. Excretion of 14CO2 in breath averaged +/- without treatment and +/- with treatment (p less than 0.005). Plasma levels of albendazole sulfoxide were measured 4 hours after the morning dose during the first and second half of the 4-week treatment cycles. In nine of the 12 patients albendazole sulfoxide levels decreased during the second half of the cycle by an average of 0.84 +/- 0.76 mumol/L (p less than 0.02). Transaminase levels increased in 10 of the 12 patients during long-term albendazole treatment, and major side effects, including hepatotoxicity, neutropenia, and alopecia, were observed in three patients. We conclude that albendazole partially inhibits microsomal enzyme function but induces its own metabolism. Hepatotoxicity and other possible severe side effects necessitate close therapeutic monitoring of patients who are given albendazole.


    PubMed Central

    Amar-Costesec, Alain; Beaufay, Henri; Wibo, Maurice; Thinès-Sempoux, Denise; Feytmans, Ernest; Robbi, Mariette; Berthet, Jacques


    Liver homogenates have been submitted to quantitative fractionation by differential centrifugation. Three particulate fractions: N (nuclear), ML (large granules), and P (microsomes), and a final supernate (S) have been obtained. The biochemical composition of the microsomal fraction has been established from the assay and distribution pattern of 25 enzymatic and chemical constituents. These included marker enzymes for mitochondria (cytochrome oxidase), lysosomes (acid phosphatase and N-acetyl-β-glucosaminidase), and peroxisomes (catalase). The microsomal preparations were characterized by a moderate contamination with large cytoplasmic granules (only 6.2% of microsomal protein) and by a high yield in microsomal components. Enzymes such as glucose 6-phosphatase, nucleoside diphosphatase, esterase, glucuronyltransferase, NADPH cytochrome c reductase, aminopyrine demethylase, and galactosyltransferase were recovered in the microsomes to the extent of 70% or more. Another typical behavior was shown by 5'-nucleotidase, alkaline phosphatase, alkaline phosphodiesterase I, and cholesterol, which exhibited a "nucleomicrosomal" distribution. Other complex distributions were obtained for several constituents recovered in significant amount in the microsomes and in the ML or in the S fraction. PMID:4150489

  6. Toxic dark effects of protoporphyrin on the cytochrome P-450 system in rat liver microsomes.

    PubMed Central

    Williams, M; Van der Zee, J; Van Steveninck, J


    In erythropoietic protoporphyria, accumulation of protoporphyrin has been found in various tissues and liver cirrhosis occurs frequently in this disease, probably due to toxic dark effects of protoporphyrin. We have studied the effect of porphyrins on various enzymic functions in rat liver microsomes. Incubation of microsomes with protoporphyrin resulted in a concentration-dependent inhibition of the oxidation of 7-ethoxycoumarin and aminopyrine by the cytochrome P-450 system. Kinetic analysis showed a decrease in Vmax., whereas the Km was not affected (non-competitive inhibition). Furthermore, reduction of cytochrome c by the NADPH-cytochrome P-450 reductase and by the NADH-cytochrome b5 reductase was inhibited. However, the activity of the reductases was only affected when the microsomes were pre-incubated with protoporphyrin, and it was found that the inhibition was dependent on the duration of the pre-incubation. Kinetic analysis again revealed non-competitive inhibition. When these experiments were repeated with uroporphyrin, no inhibition could be observed. With Stern-Volmer plots it was demonstrated that this was most likely caused by the localization of the porphyrins: protoporphyrin is localized in the membrane, whereas uroporphyrin remains in solution. From these results it is concluded that accumulation of protoporphyrin in the liver may markedly affect the cytochrome P-450 system and thus its detoxification function. PMID:1332695

  7. Prevention of LDL-suppression of HMG-CoA reductase (HMGR) activity by progesterone (PG): evidence for cytochrome P-450 involvement

    SciTech Connect

    Sexton, R.C.; Gupta, A.; Panini, S.R.; Rudney, H.


    Incubation of rat intestinal epithelial cells (IEC-6) with PG has been reported by us to prevent the suppression of HMGR activity by LDL. In the present study, addition of LDL and PG to IEC-6 cells resulted in a 2 fold increase in cellular free cholesterol (CH) in 24 h, while HMGR activity remained elevated. PG did not affect the internalization and degradation of (/sup 125/I) LDL nor the accumulation of free (/sup 3/H) CH in cells incubated with (/sup 3/H-cholesteryl linoleate)-LDL. Also, PG did not affect the intracellular transport of LDL-derived (/sup 3/H) CH to the plasma membrane nor the efflux of the (/sup 3/H) CH into medium containing human high density lipoprotein. Addition of LDL to cells, in which the cellular CH was radiolabeled from (/sup 3/H) acetate, resulted in an increased formation of radiolabeled oxysterols, detected by HPLC, and a corresponding decrease in HMGR activity. PG attenuated both the LDL-induced formation of oxysterols and suppression of HMGR activity. PG inhibited cytochrome P-450 dependent oxidation of benzphetamine, aminopyrine and aniline by liver microsomes from phenobarbitol treated rats. These results suggest PG may prevent LDL suppression of HMGR activity in IEC-6 cells by inhibiting cytochrome P-450 dependent formation of regulatory oxysterols.

  8. Discrimination and quantification of cocaine and adulterants in seized drug samples by infrared spectroscopy and PLSR.


    Grobério, Tatiane S; Zacca, Jorge J; Botelho, Élvio D; Talhavini, Marcio; Braga, Jez W B


    Middle infrared spectroscopy and multivariate analysis have been applied for the development of methods to perform both quantitative and qualitative analysis of real drug samples seized by the Brazilian Police Federal (BPF). Currently, quantification of cocaine and determination of adulterants in seizures is performed using gas chromatography with flame ionization detection. However, this technique requires a relatively complex sample preparation, higher time of analysis, the destruction of sample and a high cost. In this context, this paper presents a simpler method to quantify cocaine and its major adulterants in seized materials. Out of 375 seizures, taken within a time frame of 2009-2013. A total of 1085 samples were analyzed of which 500 were selected for the calibration set and 585 for the validation set. Cocaine concentration in seized samples was determined by using middle infrared spectroscopy and partial least squares regression (PLSR), obtaining an average prediction error of 3.0% (w/w), precision of 2.0 and 11.8% (w/w) of minimum detectable cocaine concentration in a range varying from 24.2 to 99.9% (w/w). Results indicate that the developed method is able to discriminate between cocaine hydrochloride and free base samples, to quantify cocaine content as well as to estimate the concentration of main adulterants phenacetin, benzocaine, caffeine, lidocaine and aminopyrine. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Alteration in metabolism and toxicity of acetaminophen upon repeated administration in rats.


    Kim, Sun J; Lee, Min Y; Kwon, Do Y; Kim, Sung Y; Kim, Young C


    Our previous studies showed that administration of a subtoxic dose of acetaminophen (APAP) to female rats increased generation of carbon monoxide from dichloromethane, a metabolic reaction catalyzed mainly by cytochrome P450 (CYP) 2E1. In this study we examined the changes in metabolism and toxicity of APAP upon repeated administration. An intraperitoneal dose of APAP (500 mg/kg) alone did not increase aspartate aminotransferase, alanine aminotransferase, or sorbitol dehydrogenase activity in serum, but was significantly hepatotoxic when the rats had been pretreated with an identical dose of APAP 18 h earlier. The concentrations and disappearance of APAP and its metabolites in plasma were monitored for 8 h after the treatment. APAP pretreatment reduced the elevation of APAP-sulfate, but increased APAP-cysteine concentrations in plasma. APAP or APAP-glucuronide concentrations were not altered. Administration of a single dose of APAP 18 h before sacrifice increased microsomal CYP activities measured with p-nitrophenol, p-nitroanisole, and aminopyrine as probes. Expression of CYP2E1, CYP3A, and CYP1A proteins in the liver was also elevated significantly. The results suggest that administration of APAP at a subtoxic dose may result in an induction of hepatic CYP enzymes, thereby altering metabolism and toxicological consequences of various chemical substances that are substrates for the same enzyme system.

  10. Microsomal enzyme activity, glutathione S-transferase-placental form expression, cell proliferation, and vitamin A stores in livers of rats consuming Great Lakes salmon.


    Iverson, F; Mehta, R; Hierlihy, L; Gurofsky, S; Lok, E; Mueller, R; Bourbonnais, D H; Spear, P A


    Male and female Sprague-Dawley rats were fed diets incorporating lyophilized chinook salmon obtained from Lake Ontario and Lake Huron. After 70 days, females were bred and the progeny (F1) were reared on the same fish-based diets as the adults (F0). After 78-133 days on the diets, males and females of both generations were sacrificed and hepatic microsomal enzyme activities determined, along with glutathione S-transferase-placental form (GSTP) expression and hepatic cellular proliferation. Hepatic P450 enzyme activities (MROD, EROD, PROD, BROD, and aminopyrine) were increased significantly by fish diets from both sources. Increases in hepatic enzyme activity were greatest for fish caught from Lake Ontario and reflected the total levels of organochlorine contaminants in the fish. GSTP and cell proliferation rates did not show any diet-related or dose-related changes. Vitamin A stores were analyzed as the concentration of liver retinyl palmitate. In rats receiving the highest TEQ dose (i.e., 20% Lake Ontario fish diet), vitamin A stores were significantly lower in F0 adults, F1 weanlings, and F1 adult females.

  11. Inhibition of monoamine oxidase by furazolidone in the chicken and the influence of the alimentary flora thereon.

    PubMed Central

    Ali, B. H.; Bartlet, A. L.


    1 The addition of furazolidone to the feed at the therapeutic level (0.04% w/w, 10 days) inhibited monoamine oxidase (MAO) activity by 47 to 72% in chicken duodenal mucosa, heart and brain, but in the liver the enzyme activity was unaffected by the treatment. 2 Furazolidone (200 mg/kg) administered by crop tube inhibited MAO activities in duodenal mucosa, liver, heart and brain. 3 Furazolidone (200 mg/kg) injected intramuscularly did not inhibit MAO activity in the chicken. 4 Pretreatment of the chickens with intramuscular neomycin did not antagonize the inhibition of MAO activity produced by furazolidone (200 mg/kg, crop tube). 5 Pretreatment with neomycin by crop tube to suppress the alimentary flora significantly reduced the effect of furazolidone on MAO activity, suggesting that the drug was transformed by the alimentary flora to an active metabolite which subsequently inhibited MAO activity in other organs. 6 Furazolidone in the feed (0.04% w/w, 10 days) or administered by crop tube (200 mg/kg) had no effect on the activity of aminopyrine demethylase in chicken liver. 7 The activity of aspartate transaminase in plasma was unaffected by the addition of furazolidone to the feed (0.04% w/w, 10 days). PMID:7470738

  12. Inhibition of monoamine oxidase by furazolidone in the chicken and the influence of the alimentary flora thereon.


    Ali, B H; Bartlet, A L


    1 The addition of furazolidone to the feed at the therapeutic level (0.04% w/w, 10 days) inhibited monoamine oxidase (MAO) activity by 47 to 72% in chicken duodenal mucosa, heart and brain, but in the liver the enzyme activity was unaffected by the treatment. 2 Furazolidone (200 mg/kg) administered by crop tube inhibited MAO activities in duodenal mucosa, liver, heart and brain. 3 Furazolidone (200 mg/kg) injected intramuscularly did not inhibit MAO activity in the chicken. 4 Pretreatment of the chickens with intramuscular neomycin did not antagonize the inhibition of MAO activity produced by furazolidone (200 mg/kg, crop tube). 5 Pretreatment with neomycin by crop tube to suppress the alimentary flora significantly reduced the effect of furazolidone on MAO activity, suggesting that the drug was transformed by the alimentary flora to an active metabolite which subsequently inhibited MAO activity in other organs. 6 Furazolidone in the feed (0.04% w/w, 10 days) or administered by crop tube (200 mg/kg) had no effect on the activity of aminopyrine demethylase in chicken liver. 7 The activity of aspartate transaminase in plasma was unaffected by the addition of furazolidone to the feed (0.04% w/w, 10 days).

  13. Protective and curative effects of polyphenolic extracts from Ichnocarpus frutescense leaves on experimental hepatotoxicity by carbon tretrachloride and tamoxifen.


    Kumarappan, Chidambaram; Vijayakumar, Madhavan; Thilagam, Ellappan; Balamurugan, Manikam; Thiagarajan, Madheswaran; Senthil, Siddan; Das, Sunil C; Mandal, Subhash C


    The aim of this study was to investigate prophylactic and curative effect of polyphenolic extract of Ichnocarpus frutescense against carbon tetrachloride and tamoxifen induced hepatotoxicity in rats. Carbon tetrachloride and tamoxifen caused liver damage in rats manifested by significant rise in serum enzymes levels. Models of carbon tetrachloride and tamoxifen intoxication elicited significant declines in the reduced glutathione concomitant with significant elevations in malondialdehyde levels. The oral administration of polyphenolic extract to carbon tetrachloride and tamoxifen intoxicated ats, produced significant increments in the reduced glutathione concomitant with significant decrements in malondialdehyde and liver transaminases levels. Prophylactic and curative treatments with the polyphenolic extract generally resulted in a relatively good protection against both carbon tetrachloride and tamoxifen intoxicated rats. The histopathological changes of liver sections showed an improved histological appearance. The extract inhibits CYP monoxygenases aminopyrine-N-demethylase and aniline hydroxylase, suggesting a plausible hepatoprotective mechanism. However prophylactic treatment with the polyphenolic extract exhibited a higher activity compared to curative treatment. The normalization of phenobarbitone induced sleeping time suggests the restoration of liver CYP enzymes. The study shows that hepatoprotective activity of polyphenol extract is by regulating the levels of hepatic microsomal drug metabolising enzymes. These results supported the use of this plant for the treatment of hepatitis in oriental traditional medicine.

  14. Enhanced intracellular calcium promotes metabolic and secretory disturbances in rat gastric mucosa during ethanol-induced gastritis.


    Hernández-Rincón, Ileana; Olguín-Martínez, Marisela; Hernández-Muñoz, Rolando


    Changes in the Ca(2+) homeostasis have been implicated in cell injury and death. However, Ca(2+) participation in ethanol-induced chronic gastric mucosal injury has not been elucidated. We have developed a model of ethanol-induced chronic gastric injury in rats, characterized by marked alterations in plasma membranes from gastric mucosa and a compensatory cell proliferation, which follows ethanol withdrawal. Therefore, the present study explored the possible role of intracellular Ca(2+) in the oxidative metabolism and in acid secretion in this experimental model. Glucose oxidation was greatly enhanced in the injured mucosa, as evaluated by CO(2) production by isolated mucosal preparations incubated with (14)C-radiolabeled glucose in different carbons. Oxygen consumption and acid secretion (aminopyrine accumulation) were also stimulated. A predominating secretory status was morphologically identified by electron microscopy in oxyntic cells of gastric mucosa from ethanol-treated rats. A coupling between secretory and metabolic effects induced by ethanol (demonstrated by an inhibitory effect of omeprazole in both parameters) was found. These ethanol-induced effects were also inhibited by addition of Ca(2+) chelators to isolated gastric mucosa samples. Lanthanum, a Ca(2+) channel blocker, inhibited ethanol-promoted increase of oxidative metabolism. In addition, a stimulated Ca(2+) uptake by mucosal minces and increased in vivo Ca(2+) levels in cytosolic and mitochondrial fractions, were also noticed. Enhanced glucose and oxygen consumptions were associated with higher ATP and NADP+ availability, whereas cytosolic NAD/NADH ratio (assessed by mucosal levels of lactate and pyruvate) was not significantly modified by the chronic ethanol administration. In conclusion, changes in Ca(2+) homeostasis, probably mainly due to increased extracellular Ca(2+) uptake, could mediate secretory and metabolic alterations found in the gastric mucosa from rats chronically treated with

  15. Effects of triclosan on the detoxification system in the yellow catfish (Pelteobagrus fulvidraco): expressions of CYP and GST genes and corresponding enzyme activity in phase I, II and antioxidant system.


    Ku, Peijia; Wu, Xiaoyan; Nie, Xiangping; Ou, Ruikang; Wang, Lan; Su, Tian; Li, Yigang


    Triclosan (TCS), a broad-spectrum antibacterial agent widely used in pharmaceuticals and personal case products (PPCPs), has been universally detected in aquatic ecosystem in recent years. Unfortunately, there is limited information about its potential impacts on responses of genes and enzymes related to fish detoxification. In the present work, we cloned CYP3A and alpha-GST of yellow catfish (Pelteobagrus fulvidraco) and tested the transcriptional expression of CYP1A, CYP3A and GST as well as the alterations of their corresponding enzymes, including ethoxyresorufin-O-deethylase (EROD), aminopyrine N-demethylase (APND), erythromycin N-demethylase (ERND), glutathione S-transferase (GST) and catalase (CAT), and also the oxidative product malondialdehyde (MDA) content in the liver of P. fulvidraco exposed to TCS. Amino acids of CYP3A and GST were deduced and phylogenetic tree was constructed respectively. High identity percent was exhibited between P. fulvidraco and other species, such as other fish, birds and mammals. Results indicated that TCS significantly elevated CYP1A and GST but decreased CYP3A expression, EROD activity and MDA content at lower concentrations of TCS at 24h. Moreover, CYP3A and GST were significantly inhibited at 72 h but induced at 168 h at lower concentrations. However, CYP3A was always induced at the highest concentration during the exposure period. Furthermore, CYP3A, GST, GST enzyme and MDA content exhibited a dose-effect relationship to some extent, but no significant responses were observed in ERND, APND and CAT except for individual treatments. Taken together, EROD was the most sensitive to TCS exposure as compared to other enzymes. Meanwhile, mRNA responses were more sensitive in yellow catfish. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Drug metabolizing enzyme systems in the houbara bustard (Chlamydotis undulata).


    Bailey, T A; John, A; Mensah-Brown, E P; Garner, A; Samour, J; Raza, H


    This study compared catalytic and immunochemical properties of drug metabolizing phase I and II enzyme systems in houbara bustard (Chlamydotis undulata) liver and kidney and rat liver. P450 content in bustard liver (0.34 +/- 0.03 nmol mg-1 protein) was 50% lower than that of rat liver (0.70 +/- 0.02 nmol mg-1 protein). With the exception of aniline hydroxylase activity, monooxygenase activities using aminopyrine, ethoxyresorufin and ethoxycoumarin as substrates were all significantly lower than corresponding rat liver enzymes. As found in mammalian systems the P450 activities in the bird liver were higher than in the kidney. Immunohistochemical analysis of microsomes using antibodies to rat hepatic P450 demonstrated that bustard liver and kidney express P4502C11 homologous protein; no appreciable cross-reactivity was observed in bustards using antibodies to P4502E1, 1A1 or 1A2 isoenzymes. Glutathione content and glutathione S-transferase (GST) activity in bustard liver were comparable with those of rat liver. GST activity in the kidney was 65% lower than the liver. Western blotting of liver and kidney cytosol with human GST isoenzyme-specific antibodies revealed that the expression of alpha-class of antibodies exceeds mu in the bustard. In contrast, the pi-class of GST was not detected in the bustard liver. This data demonstrates that hepatic and renal microsomes from the bustard have multiple forms of phase I and phase II enzymes. The multiplicity and tissue specific expression of xenobiotic metabolizing enzymes in bustards may play a significant role in determining the pharmacokinetics of drugs and susceptibility of the birds to various environmental pollutants and toxic insults.

  17. Pulmonary uptake of morphine (M)

    SciTech Connect

    Roerig, D.L.; Bunke, S.S.; Kotrly, K.J.; Dawson, C.A.; Kampine, J.P.


    Previously the authors reported less than 5% of M was taken up during the first pass through the human lung. The low uptake of this basic lipophilic amine was further investigated in a single pass isolated perfused rat lung (IPL) in comparison to uptake of radiolabelled H/sub 2/O, antipyrine (A), aminopyrine (AM), nicotine (N) and phenylethylamine (P). The IPL was perfused for 5 min with each drug (5nmol/ml) and effluent collected in 10 sec fractions. Pulmonary extraction was calculated using indocyanine green dye as a non-extractable reference indicator. Accumulation of all compounds in the IPL reached an apparent equilibrium within 4 min. At equilibrium lung/perfusate conc. ratios for H/sub 2/O, A, AM, N, P and M were 1.04, 0.84, 0.85, 1.44, 2.57 and 1.13 respectively. The time course of M uptake differed from the other compounds since initial extraction of M was low (23%) compared to 75%, 53%, 35%, 82% and 86% for H/sub 2/O, A, AM, N and P respectively. Also, the half time to equilibrium for M was longer (50 sec) compared to 18, 21, 26, 19 and 22 sec for H/sub 2/O, A, AM, N and P respectively. The low initial pulmonary extraction of M compared to these compounds followed by greater M extraction during the remainder of drug infusion suggests uptake mechanisms for M different than the flow limited uptake for water and other basic amine drugs.


    PubMed Central

    Beaufay, Henri; Amar-Costesec, Alain; Thinès-Sempoux, Denise; Wibo, Maurice; Robbi, Mariette; Berthet, Jacques


    Rat liver microsomal fractions have been equilibrated in various types of linear density gradients. 15 fractions were collected and assayed for 27 constituents. As a result of this analysis microsomal constituents have been classified, in the order of increasing median density, into four groups labeled a, b, c, and d. Group a includes: monoamine oxidase, galactosyltransferase, 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and cholesterol; group b: NADH cytochrome c reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b5, and cytochrome P 450; group c: glucose 6-phosphatase, nucleoside diphosphatase, esterase, β-glucuronidase, and glucuronyltransferase; group d: RNA, membrane-bound ribosomes, and some enzymes probably adsorbed on ribosomes: fumarase, aldolase, and glutamine synthetase. Analysis of the microsomal fraction by differential centrifugation in density gradient has further dissociated group a into constituents which sediment more slowly (monoamine oxidase and galactosyltransferase) than those of groups b and c, and 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and the bulk of cholesterol which sediment more rapidly (group a2). The microsomal monoamine oxidase is attributed, at least partially, to detached fragments of external mitochondrial membrane. Galactosyltransferase belongs to the Golgi complex. Group a2 constituents are related to plasma membranes. Constituents of groups b and c and RNA belong to microsomal vesicles derived from the endoplasmic reticulum. These latter exhibit a noticeable biochemical heterogeneity and represent at the most 80% of microsomal protein, the rest being accounted for by particles bearing the constituents of groups a and some contaminating mitochondria, lysosomes, and peroxisomes. Attention is called to the operational meaning of microsomal subfractions and to their cytological complexity. PMID:4150490

  19. Toxic responses of swimming crab (Portunus trituberculatus) larvae exposed to environmentally realistic concentrations of oxytetracycline.


    Ren, Xianyun; Wang, Zhuqing; Gao, Baoquan; Liu, Ping; Li, Jian


    Oxytetracycline (OTC) is the most commonly used antibiotics for bacterial treatment in crustacean farming in China, and because of their intensive use, the potential harmful effects on aquatic organisms are of great concern. The aim of this study was to investigate the effects of oxytetracycline (OTC) on the antioxidant system, detoxification progress, and biomolecule damage in Portunus trituberculatus larvae. In this study, larvae that belonged to four zoeal stages were exposed to four different concentrations of OTC (0, 0.3, 3, and 30 μg/L) for 3 days. The results showed that the exposure to OTC significantly suppressed the antioxidant system of, especially, zoea I (Z1) and zoea II (Z2) larvae. OTC inhibited the transcriptional expression of phase I (CYP2 and CYP3) and phase II detoxification genes (GST) in a dose-dependent manner and altered the expressions of their corresponding enzymes, namely, aminopyrine N-demethylase, erythromycin N-demethylase, and glutathione S-transferase. Moreover, 0.3 μg/L OTC activated the transcription of ATP-binding cassette (ABC) transporter subfamily B (ABCB) and subfamily G (ABCG) in the Z1 and Z2 larvae, while 3 and 30 μg/L OTC suppressed all of them. Additionally, malondialdehyde content exhibited a dose- and zoea-effect relationship to some extent, but no significant differences were observed in the F values of the Z3 and Z4 larvae, except for the 30 μg/L OTC treatment. Thus, the Z3 and Z4 larvae were less sensitive to OTC exposure than the Z1 and Z2 larvae. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Effect of oxygen concentration on microsomal oxidation of ethanol and generation of oxygen radicals.

    PubMed Central

    Puntarulo, S; Cederbaum, A I


    The iron-catalysed production of hydroxyl radicals, by rat liver microsomes (microsomal fractions), assessed by the oxidation of substrate scavengers and ethanol, displayed a biphasic response to the concentration of O2 (varied from 3 to 70%), reaching a maximal value with 20% O2. The decreased rates of hydroxyl-radical generation at lower O2 concentrations correlates with lower rates of production of H2O2, the precursor of hydroxyl radical, whereas the decreased rates at elevated O2 concentrations correlate with lower rates (relative to 20% O2) of activity of NADPH-cytochrome P-450 reductase, which reduces iron and is responsible for redox cycling of iron by the microsomes. The oxidation of aniline or aminopyrine and the cytochrome P-450/oxygen-radical-independent oxidation of ethanol also displayed a biphasic response to the concentration of O2, reaching a maximum at 20% O2, which correlates with the dithionite-reducible CO-binding spectra of cytochrome P-450. Microsomal lipid peroxidation increased as the concentration of O2 was raised from 3 to 7 to 20% O2, and then began to level off. This different pattern of malondialdehyde generation compared with hydroxyl-radical production probably reflects the lack of a role for hydroxyl radical in microsomal lipid peroxidation. These results point to the complex role for O2 in microsomal generation of oxygen radicals, which is due in part to the critical necessity for maintaining the redox state of autoxidizable components of the reaction system. PMID:3415646

  1. Gastrin receptors on isolated canine parietal cells

    SciTech Connect

    Soll, A.H.; Amirian, D.A.; Thomas, L.P.; Reedy, T.J.; Elashoff, J.D.


    The receptors in the fundic mucosa that mediate gastrin stimulation of acid secretion have been studied. Synthetic human gastrin-17-I (G17) with a leucine substitution in the 15th position ((Leu15)-G17) was iodinated by chloramine T; high saturable binding was found to enzyme-dispersed canine fundic mucosal cells. /sup 127/I-(Leu15)-G17, but not /sup 127/I-G17, retained binding potency and biological activity comparable with uniodinated G17. Fundic mucosal cells were separated by size by using an elutriator rotor, and specific /sup 125/I-(Leu-15)-G17 binding in the larger cell fractions was highly correlated with the distribution of parietal cells. There was, however, specific gastrin binding in the small cell fractions, not accounted for by parietal cells. Using sequential elutriation and stepwise density gradients, highly enriched parietal and chief cell fractions were prepared; /sup 125/I-(Leu15)-G17 binding correlated positively with the parietal cell (r . 0.98) and negatively with chief cell content (r . -0.96). In fractions enriched to 45-65% parietal cells, specific /sup 125/I-(Leu15)-G17 binding was rapid, reaching a steady state at 37 degrees C within 30 min. Dissociation was also rapid, with the rate similar after 100-fold dilution or dilution plus excess pentagastrin. At a tracer concentration from 10 to 30 pM, saturable binding was 7.8 +/- 0.8% per 10(6) cells (mean +/- SE) and binding in the presence of excess pentagastrin accounted for 11% of total binding. G17 and carboxyl terminal octapeptide of cholecystokinin (26-33) were equipotent in displacing tracer binding and in stimulating parietal cell function ((/sup 14/C)aminopyrine accumulation), whereas the tetrapeptide of gastrin (14-17) had a much lower potency. Proglumide inhibited gastrin binding and selectively inhibited gastrin stimulation of parietal cell function.

  2. Mechanism of peroxidative activation of the bladder carcinogen 2-amino-4-(5-nitro-2-furyl)-thiazole (ANFT): comparison with benzidine.


    Lakshmi, V M; Mattammal, M B; Zenser, T V; Davis, B B


    The mechanism of activation of the bladder carcinogen 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) was investigated by comparison with benzidine. In comparison with benzidine, ANFT has a higher electrochemical potential (approximately 700 mV) and is less effective as a reducing co-substrate for either prostaglandin H synthase (PHS) or horseradish peroxidase. Activation was monitored by measuring binding to protein (BSA) and DNA. ANFT binding to protein was reduced by indomethacin, a fatty acid cyclooxygenase inhibitor; phenol and aminopyrine, competitive reducing co-substrates; ascorbic acid, an antioxidant; and glutathione, thioether conjugate formation. These results are consistent with those previously reported for benzidine and demonstrate a peroxide co-substrate requirement, interaction of peroxidase with amine, formation of reactive intermediates and inactivation of reactive intermediates. 5,5-Dimethyl-1-pyrroline N-oxide (DMPO), a radical trap, also reduced ANFT binding to protein. Similar results were observed whether activation by PHS or horseradish peroxidase was investigated. Peroxidative activation of ANFT and benzidine to bind DNA was inhibited by these test agents in a manner similar to that observed with protein except that DMPO did not reduce binding. In addition, 2-methyl-2-nitrosopropane and methyl viologen, which are radical traps, and methionine and p-nitrobenzyl-pyridine, which are strong nucleophiles, did not reduce ANFT or benzidine binding to DNA. These agents also did not prevent binding of benzidinediimine, the two-electron product of benzidine oxidation, to polydeoxyguanosine. Glutathione inhibited diimine binding by forming a conjugate. Results demonstrate that activation of ANFT to bind protein and DNA is similar to benzidine. Peroxidative activation of benzidine occurs by both one- and two-electron oxidation. A similar mechanism would explain ANFT binding to protein (one electron) and DNA (two electron).

  3. Breath tests: principles, problems, and promise

    SciTech Connect

    Lo, C.W.; Carter, E.A.; Walker, W.A.


    Breath tests rely on the measurement of gases produced in the intestine, absorbed, and expired in the breath. Carbohydrates, such as lactose and sucrose, can be administered in ysiologic doses; if malabsorbed, they will be metabolized to hydrogen by colonic bacteria. Since hydrogen is not produced by human metabolic reactions, a rise in breath hydrogen, as measured by gas chromatography, is evidence of carbohydrate malabsorption. Likewise, a rise in breath hydrogen marks the transit time of nonabsorbable carbohydrates such as lactulose through the small intestine into the colon. Simple end-expiratory interval collection into nonsiliconized vacutainer tubes has made these noninvasive tests quite convenient to perform, but various problems, including changes in stool pH intestinal motility, or metabolic rate, may influence results. Another group of breath tests uses substrates labeled with radioactive or stable isotopes of carbon. Labeled fat substrates such as trioctanoin, tripalmitin, and triolein do not produce the expected rise in labeled breath CO/sub 2/ if there is fat malabsorption. Bile acid malabsorption and small intestinal bacterial overgrowth can be measured with labeled cholylglycine or cholyltaurine. Labeled drugs such as aminopyrine, methacetin, and phenacetin can be used as an indication of drug metabolism and liver function. Radioactive substrates have been used to trace metabolic pathways and can be measured by scintillation counters. The availability of nonradioactive stable isotopes has made these ideal for use in children and pregnant women, but the cost of substrates and the mass spectrometers to measure them has so far limited their use to research centers. It is hoped that new techniques of processing and measurement will allow further realization of the exciting potential breath analysis has in a growing list of clinical applications.

  4. Anti-Trypanosoma cruzi effects of cyclosporin A derivatives: possible role of a P-glycoprotein and parasite cyclophilins.


    Búa, J; Fichera, L E; Fuchs, A G; Potenza, M; Dubin, M; Wenger, R O; Moretti, G; Scabone, C M; Ruiz, A M


    Cyclophilins are target molecules for cyclosporin A (CsA), an immunosuppressive antimicrobial drug. We have previously reported the in vitro anti-Trypanosoma cruzi activity of H-7-94 and F-7-62 non-immunosuppressive CsA analogues. In this work, we continue the study of the parasiticidal effect of H-7-94 and F-7-62 CsA analogues in vitro and in vivo and we analyse 3 new CsA derivatives: MeIle-4-CsA (NIM 811), MeVal-4-CsA (MeVal-4) and D-MeAla-3-EtVal-4-CsA, (EtVal-4). The most efficient anti-T. cruzi effect was observed with H-7-94, F-7-62 and MeVal-4 CsA analogues evidenced as inhibition of epimastigote proliferation, trypomastigote penetration, intracellular amastigote development and in vivo T. cruzi infection. This trypanocidal activity could be due to inhibition of the peptidyl prolyl cis-trans isomerase activity on the T. cruzi recombinant cyclophilins tested. Furthermore, CsA and F-7-62 derivative inhibited the efflux of rhodamine 123 from T. cruzi epimastigotes, suggesting an interference with a P-glycoprotein activity. Moreover, H-7-94 and F-7-62 CsA analogues were not toxic as shown by cell viability and by aminopyrine-N-demethylase activity on mammalian cells. Our results show that H-7-94, F-7-62 and MeVal-4 CsA analogues expressed the highest inhibiting effects on T. cruzi, being promissory parasiticidal drugs worthy of further studies.

  5. Primary culture of secretagogue-responsive parietal cells from rabbit gastric mucosa

    SciTech Connect

    Chew, C.S.; Ljungstroem, M.S.; Smolka, A.; Brown, M.R.


    A new procedure for isolation and primary culture of gastric parietal cells is described. Parietal cells from rabbit gastric mucosa are enriched to greater than 95% purity by combining a Nycodenz gradient separation with centrifugal elutriation. Cells are plated on the basement membrane matrix, Matrigel, and maintained in culture for at least 1 wk. Parietal cells cultured in this manner remain differentiated, cross-react with monoclonal H+-K+-ATPase antibodies, and respond to histamine, gastrin, and cholinergic stimulation with increased acid production as measured by accumulation of the weak base, (/sup 14/C)aminopyrine. When stimulated, cultured cells undergo ultrastructural changes in which intracellular canaliculi expand and numerous microvilli are observed. These ultrastructural changes are similar to those previously found to occur in vivo and in acutely isolated parietal cells. Morphological transformations in living cells can also be observed with differential interference contrast optics in the light microscope. After histamine stimulation, intracellular canaliculi gradually expand to form large vacuolar spaces. When the H2 receptor antagonist, cimetidine, is added to histamine-stimulated cells, these vacuoles gradually disappear. The ability to maintain hormonally responsive parietal cells in primary culture should make it possible to study direct, long-term effects of a variety of agonists and antagonists on parietal cell secretory-related activity. These cultured cells should also prove to be useful for the study of calcium transients, ion fluxes, and intracellular pH as related to acid secretion in single cells, particularly since morphological transformations can be used to monitor physiological responses at the same time within the same cell.

  6. Hepatic injury induces contrasting response in liver and kidney to chemicals that are metabolically activated: Role of male sex hormone

    SciTech Connect

    Kim, Young C. Yim, Hye K.; Jung, Young S.; Park, Jae H.; Kim, Sung Y.


    Injury to liver, resulting in loss of its normal physiological/biochemical functions, may adversely affect a secondary organ. We examined the response of the liver and kidney to chemical substances that require metabolic activation for their toxicities in mice with a preceding liver injury. Carbon tetrachloride treatment 24 h prior to a challenging dose of carbon tetrachloride or acetaminophen decreased the resulting hepatotoxicity both in male and female mice as determined by histopathological examination and increases in serum enzyme activities. In contrast, the renal toxicity of the challenging toxicants was elevated markedly in male, but not in female mice. Partial hepatectomy also induced similar changes in the hepatotoxicity and nephrotoxicity of a challenging toxicant, suggesting that the contrasting response of male liver and kidney was associated with the reduction of the hepatic metabolizing capacity. Carbon tetrachloride pretreatment or partial hepatectomy decreased the hepatic xenobiotic-metabolizing enzyme activities in both sexes but elevated the renal p-nitrophenol hydroxylase, p-nitroanisole O-demethylase and aminopyrine N-demethylase activities significantly only in male mice. Increases in Cyp2e1 and Cyp2b expression were also evident in male kidney. Castration of males or testosterone administration to females diminished the sex-related differences in the renal response to an acute liver injury. The results indicate that reduction of the hepatic metabolizing capacity induced by liver injury may render secondary target organs susceptible to chemical substances activated in these organs. This effect may be sex-specific. It is also suggested that an integrated approach should be taken for proper assessment of chemical hazards.

  7. Determination of selected pharmaceuticals in tap water and drinking water treatment plant by high-performance liquid chromatography-triple quadrupole mass spectrometer in Beijing, China.


    Cai, Mei-Quan; Wang, Rong; Feng, Li; Zhang, Li-Qiu


    A simultaneous determination method of 14 multi-class pharmaceuticals using solid-phase extraction (SPE) followed by high-performance liquid chromatography-tandem mass spectrometer (HPLC-MS/MS) was established to measure the occurrence and distribution of these pharmaceuticals in tap water and a drinking water treatment plant (DWTP) in Beijing, China. Target compounds included seven anti-inflammatory drugs, two antibacterial drugs, two lipid regulation drugs, one antiepileptic drug, and one hormone. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.01 to 1.80 ng/L and 0.05 to 3.00 ng/L, respectively. Intraday and inter-day precisions, recoveries of different matrices, and matrix effects were also investigated. Of the 14 pharmaceutical compounds selected, nine were identified in tap water of Beijing downtown with the concentration up to 38.24 ng/L (carbamazepine), and the concentration levels of detected pharmaceuticals in tap water (<5 ng/L for most pharmaceuticals) were lower than previous studies in other countries. In addition, ten and six pharmaceuticals were measured in raw water and finished water at the concentration ranged from 0.10 to 16.23 and 0.13 to 17.17 ng/L, respectively. Five compounds were detected most frequently in DWTP, namely antipyrine, carbamazepine, isopropylantipyrine, aminopyrine, and bezafibrate. Ibuprofen was found to be the highest concentration pharmaceutical during DWTP, up to 53.30 ng/L. DWTP shows a positive effect on the removal of most pharmaceuticals with 81.2-99.5 % removal efficiencies, followed by carbamazepine with 55.4 % removal efficiency, but it has no effect for removing ibuprofen and bezafibrate.

  8. Proton pump inhibition--the ultimate control of acid secretion

    SciTech Connect

    Zdon, M.J.; Ballantyne, G.H.; Schafer, D.E.; Tyshkov, M.; Cambria, R.P.; Modlin, I.M.


    The cellular mechanisms of acid secretion by the parietal cell (PC) include stimulation of membrane receptors, increases in cytosolic cyclic AMP levels, and activation of protein kinase systems. These events culminate in stimulation of a membrane-based proton pump. This consists of a non-electrogenic H+-K+-ATPase which transports H+ ions into the secretory canaliculus of the PC in exchange for the cation K+. It has been proposed that blockade of this proton pump would result in inhibition of acid secretion by all classes of acid secretagogues. Thus, the effects of membrane receptor agonists as well as any agents which augment cellular cAMP levels should be inhibited. Substituted benzimidazoles are weak bases which prevent acid secretion by blocking the H+-K+-ATPase system. In order to test the above hypothesis, we investigated the effects of the substituted benzimidazole H168/68 and cimetidine (C) on histamine (H) and 8B-stimulated acid secretion. The rabbit isolated gastric gland (IGG) model was used and acid secretion assessed by the accumulation of /sup 14/C-labeled weak base aminopyrine (AP) within the IGG in response to secretagogue stimulation. H168/68 and C both inhibited H (5 X 10(-5) M)-stimulated (/sup 14/C)AP accumulation in a concentration-dependent manner (P less than 0.05). H168/68 inhibited both H- and 8B-stimulated (/sup 14/C)AP accumulation (P less than 0.05), while C inhibited only H-stimulated (/sup 14/C)AP accumulation (P less than 0.05). H168/68 suppressed (/sup 14/C)AP below even unstimulated levels of (/sup 14/C)AP accumulation. These results support the hypothesis that H168/68 inhibits the PC distal to cAMP stimulation.

  9. Effect of repeated ether anesthesias on the mono-oxygenase system of rat liver S-9 fraction.


    Paolini, M; Bauer, C; Corsi, C; Tonelli, F; Hrelia, P; Bronzetti, G; Forti, G C


    This study was designed to investigate the effect of ether anesthesia in rats, before i.p. injections to induce the mono-oxygenase enzyme system, on biochemical properties of liver S9 fractions. Aminopyrine N-demethylase and rho-nitroanisole O-demethylase activity levels, their stability, and lipid peroxidation were determined in S9 fractions after etherization (about 1 min in ether vapor chamber daily for 3 consecutive days, before i.p. injections of Na-phenobarbital and beta-naphthoflavone) and compared with controls receiving the same injections without etherization. The activities were slightly (but not significatively) enhanced after this treatment, but stability was markedly and significatively greater after 1 h of incubation in the conditions of the liver microsomal assay (+ 14.8% and + 74.7%, respectively); lipid peroxidation was strongly and significatively depressed (-76.0%). Etherization sufficient to kill the animals on the 4th day resulted in equally active but less stable S9 fraction enzymes. Dimethylnitrosamine (as a standard premutagen) was assayed with the D7 strain of Saccharomyces cerevisiae using S9 fractions obtained from both anesthetized and nonanesthetized rats. According to biochemical data, results obtained with S9 from partially anesthetized rats were comparable with the conventional ones (S9 from nonanesthetized rats). On the contrary, the use of more prolonged ether anesthesia, including one on the day the animals are killed, gives S9 fraction significantly less effective. We conclude that if brief etherizations are used, for i.p. injections only, the S9 fractions obtained are entirely satisfactory and the procedures involved in production are simplified; the additional animal treatment (etherization) must be specified.

  10. Effects of neem flowers, Thai and Chinese bitter gourd fruits and sweet basil leaves on hepatic monooxygenases and glutathione S-transferase activities, and in vitro metabolic activation of chemical carcinogens in rats.


    Kusamran, W R; Ratanavila, A; Tepsuwan, A


    The objectives of this study were to determine the effects of feeding of four vegetables commonly consumed in Thailand, namely, flowers of the neem tree (Azadirachta indica var. siamensis), fruits of Thai and the Chinese bitter gourd (Momordica charantia Linn.) and leaves of sweet basil (Ocimum basilicum Linn) on the levels of phase I enzymes, which include cytochrome P450 (P450), aniline hydroxylase (ANH) and aminopyrine-N-demethylase (AMD) as well as the capacity to activate the mutagenicities of aflatoxin B1 (AFB1) and benzo[a]pyrene (BaP), and to induce the phase II enzymes [i.e. glutathione S-transferase (GST)] in rat liver. It was found that feeding of the diets containing 12.5% neem flowers and Thai bitter gourd fruits for 2 weeks strongly enhanced GST activity, 2.7- and 1.6- fold of the pair-fed control values, respectively, while resulting in a marked reduction of the levels of most phase I reactions. Fruits of the Chinese bitter gourd, which is in the same species as Thai bitter gourd, had no effect on GST activity but decreased AMD activity and the in vitro metabolic activation of AFB1 and BaP. On the other hand, however, dietary sweet basil leaves caused a significant increase in the levels of both GST and all phase I enzymes. Results in the present study clearly demonstrate that neem flowers and Thai bitter gourd fruits contain monofunctional phase II enzyme inducers and compounds capable of repressing some monooxygenases, especially those involved in the metabolic activation of chemical carcinogens, while sweet basil leaves contain compounds, probably bifunctional inducers, capable of inducing both phase I and phase II enzymes and Chinese bitter gourd fruits contain only compounds capable of repressing some monooxygenases. These results therefore suggest that neem flowers and Thai bitter gourd fruits may possess chemopreventive potential, while those of Chinese bitter gourd fruits and sweet basil leaves are uncertain.

  11. Regulation of hydrogen ion secretion in rat gastric mucosal parietal cells isolated by centrifugal elutriation

    SciTech Connect

    Thompson, W.J.; Black, E.W.; Strada, S.J.


    To study the second messengers, cyclic AMP (cA) and calcium as regulators of gastric acid secretion, the authors have developed a method to isolate and enrich parietal cells (PC) from rat gastric mucosa by centrifugal elutriation. After mucosal dispersion with Pronase/EDTA in KRB buffer containing glucose and albumin, cells are elutriated with a four step washout procedure. The PC fraction is 60-80% pure with 95% viability and yields of 40-60%. PC cells are used to identify calcium/calmodulin and cA-mediated protein phosphorylations. CA level is measured with a solid phase radioimmunoassay using sample acetylation and hydrogen ion production is determined indirectly by /sup 14/C-aminopyrine (AP) accumulation. PC-rich (PCR) and PC-poor (PCP) fractions show similar basal cA content (380 fmol/million cells) but have markedly different responses to secretagogues in both rate and magnitude. AP and cA correlate with stimulation induced by forskolin (F) and histamine (H) but not carbachol. F increases cA 14 fold linearly for 60 min in PCP and 180 fold in PCR. H gives a weak 1 fold cA increase in PCP with little change in AP, but shows a 10 fold increase in cA and an 8 fold increase in AP in PCR. No changes in cA are observed with carbachol induced AP accumulation. These data support the role of cA in regulation of acid secretion and demonstrate the utility of centrifugal elutriation as a method to obtain parietal cells from rat gastric mucosa.

  12. Effects of selenium on 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis and DNA adduct formation

    SciTech Connect

    Ip, C.; Daniel, F.B.


    The purpose of the present investigation was to determine the effects of dietary selenium deficiency or excess on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary neoplasia in rats and to delineate whether selenium-mediated modification of mammary carcinogenesis was associated with changes in carcinogen:DNA adduct formation and activities of liver microsomal enzymes that are involved in xenobiotic metabolism. Female Sprague-Dawley rats were divided into three groups from weaning and were maintained on one of three synthetic diets designated as follows: selenium deficient (less than 0.02 ppm); selenium adequate (0.2 ppm); or selenium excess (2.5 ppm). For the DMBA binding and DNA adduct studies, rats were given a dose of (/sup 3/H)DMBA p.o. after 1 month on their respective diets. Results from the liver and the mammary gland indicated that neither selenium deficiency nor excess had any significant effect on the binding levels, which were calculated on the basis of total radioactivity isolated with the purified DNA. Furthermore, it was found that dietary selenium intake did not seem to affect quantitatively or qualitatively the formation of DMBA:DNA adducts in the liver. Similarly, in a parallel group of rats that did not receive DMBA, the activities of aniline hydroxylase, aminopyrine N-demethylase, and cytochrome c reductase were not significantly altered by dietary selenium levels. Concurrent with the above experiments, the effect of dietary selenium intake on carcinogenesis was also monitored. Results of this experiment indicated that selenium deficiency enhanced mammary carcinogenesis only when this nutritional condition was maintained in the postinitiation phase. Likewise, an excess of selenium intake inhibited neoplastic development only when this regimen was continued after DMBA administration.

  13. Toxicity and microsomal enzyme induction effects of several polybrominated biphenyls of Firemaster.


    Dannan, G A; Sleight, S D; Aust, S D


    Some toxicological and pharmacological effects of 2,4,5,2',5'-penta- (congener 1), 2,3,4,2',4',5'-hexa- (congener 5), 2,4,5,3',4',5'-hexa- (congener 6), 2,3,4,5,3',4',-hexa- (congener 7), and 2,3,4,5,2',3',4'-heptabromobiphenyl (congener 9) were evaluated in male rats given a single 90 mg/kg ip injection and killed seven days later. Only congener 7 depressed body weight gain, spleen and thymus weights, and caused severe histopathological changes in the thymus. Congener 7 caused the largest increase in liver weight and the most changes in liver pathology while congener 1 failed to enlarge this organ and caused the mildest ultrastructural changes. Liver microsomes were isolated and evaluated for enzyme induction from all treated rats except those administered congener 6, which was previously identified as a mixed-type enzyme inducer (Dannan et al., 1978b). All congeners increased the liver microsomal cytochrome P-450 content, but only congener 7 shifted the carbon monoxide difference spectrum absorption maximum to 448.0 nm. The microsomal ethyl isocyanide difference spectrum 455/430 nm ratio was increased the most by congener 7 (3 fold). All congeners increased cytochrome P-450 reductase and microsomal epoxide hydrase activities by nearly 1.5-3 fold. Congener 7 failed to induce aminopyrine-N-demethylase activity but the remaining congeners increased it by 2 fold. Congener 7 was the most effective inducer of benzo[a]pyrene hydroxylase and p-nitrophenol UDP-glucuronyl transferase. These results add to the suggestion that the presence of an ortho halogen on a polyhalogenated biphenyl does not completely abolish toxicity or 3-methylcholanthrene-type microsomal enzyme induction.

  14. Characterization of substrate specificity of dog CYP1A2 using CYP1A2-deficient and wild-type dog liver microsomes.


    Mise, Masashi; Hashizume, Takanori; Komuro, Setsuko


    Beagle dogs are commonly used for toxicological and pharmacological studies of drug candidates in the pharmaceutical industry. Recently, we reported a CYP1A2-deficient dog with a nonsense mutation (C1117T). In this study, using CYP1A2-deficient and wild-type dog liver microsomes, substrate specificity of dog CYP1A2 was investigated and compared with human CYP1A2. For this purpose, 11 cytochrome P450 assays were conducted in human or dog liver microsomes, genotyped for the CYP1A2 C1117T mutation. There was no statistical difference between C/C, C/T, and T/T dogs in activities of aminopyrine N-demethylase, aniline hydroxylase, bufuralol 1'-hydroxylase, and midazolam 1'-hydroxylase. On the other hand, activities of phenacetin O-deethylase, ethoxyresorufin O-deethylase, and tacrine 1-hydroxylase, which were catalyzed by human CYP1A2, were significantly lower in T/T dogs than C/C dogs, indicating that dog and human CYP1A2 was responsible for these activities. However, dog CYP1A2 was not involved in caffeine metabolism, a marker activity for human CYP1A2. As for endogenous substances, our results indicated that human CYP1A2, but not dog CYP1A2, is responsible for melatonin 6-hydroxylase, 9-cis-retinal oxidase, and estradiol 2-hydroxylase activity. In conclusion, tacrine, ethoxyresorufin, and phenacetin are probe substrates for CYP1A2 not only in humans but also in dogs. However, caffeine, melatonin, 9-cis-retinal, and estradiol, which are substrate for human CYP1A2, are not good substrates for dog CYP1A2. The finding that there are species differences in substrate specificity of CYP1A2 between humans and beagle dogs is an important issue and must be considered for preclinical studies using beagle dogs.

  15. Induction profiles of P450 in rat liver microsomes by pyrazole or methylpyrazole

    SciTech Connect

    Krikun, G.; Cederbaum, A.I.


    Rats were injected for 2-3 days with pyrazole (P) or 4-methylpyrazole (MP) potent inhibitors of alcohol dehydrogenase. While P treatment induced a P450 isozyme with MW 52,000 as seen on SDS gels, MP induced 2 or 3 P450s. One of the P450s induced by MP appeared to be similar to the one increased by P treatment. The increase of 2-3 bands by MP correlated with a two fold increased in total P450 content. Microsomes from the P treated rats displayed increased activity (per mg protein or per nmole P450) with aniline, p-nitroanisole, dimethylnitrosamine (low Km DMN) and ethanol as substrates, but not with aminopyrine, ethoxycoumarin or DMN (high Km). A stereochemical preference for + 2-butanol over the -isomer was also observed. Kinetic experiments indicated that P treatment increased the Vmax for ethanol, aniline and + 2-butanol. These properties are similar to those found after chronic ethanol treatment. MP treatment resulted in an increased in the oxidation of all the drugs and alcohols tested, primarily due to the increase in content of P450. In analogy to results with P, MP treatment also resulted in stereochemical preference for + vs -2-butanol, and increased turnover numbers with aniline and p-nitroanisole. However in contrast to P, no increase in turnover number with ethanol, + 2-butanol or DMN (low Km) was found after MP treatment. It is probable that these divergent effects are due to the induction of several isozymes, one of which has properties similar to that induced by P. Thus, P induces a P450 similar to that induced by ethanol whereas MP induces that isozyme in addition to others.

  16. Effects of tin-protoporphyrin administration on hepatic xenobiotic metabolizing enzymes in the juvenile rat

    SciTech Connect

    Stout, D.L.; Becker, F.F.


    The heme analogue tin-protoporphyrin IX (SnP) is a potent inhibitor of microsomal heme oxygenase. Administration of SnP to neonatal rats can prevent hyperbilirubinemia by blocking the postnatal increase of heme oxygenase activity. Apparently innocuous at therapeutic doses, it is of potential clinical value for chemoprevention of neonatal jaundice. We found that when 50-g male Sprague-Dawley rats were treated daily with 50 mumol of SnP/kg sc for 6 days, hepatic microsomal cytochromes b5 and P-450 were significantly diminished. Cytochrome P-450 reductase, two P-450-dependent monooxygenases, aminopyrine demethylase and benzo(a)pyrene hydroxylase, and catalase, a peroxisomal hemoprotein, were also significantly diminished. These results suggested that SnP might significantly affect the metabolism of other xenobiotics. This possibility was confirmed by the finding that hexobarbital-induced sleep lasted 4 times longer in SnP-treated rats than in controls. Inhibition of protein synthesis by SnP was ruled out as the cause of hemoprotein loss when administration of (/sup 3/H)leucine to SnP-treated and control rats demonstrated that proteins of the microsomal, cytosolic, and plasma membrane fractions of the livers from both groups incorporated similar levels of leucine. When /sup 55/FeCl/sub 3/ and (2-/sup 14/C)glycine were administered to measure heme synthesis, heme extract from the livers of SnP-treated rats contained 4 times more label from iron and glycine than did heme from control livers. Despite the apparent increased rate of heme synthesis in SnP-treated rats, each of the three cell fractions demonstrated a significant loss of heme but contained sizable amounts of SnP. These findings suggest that SnP causes a decrease of functional hemoprotein and partial loss of enzymic activity by displacing intracellular heme.

  17. Decolourization of azo dye methyl red by Saccharomyces cerevisiae MTCC 463.


    Jadhav, J P; Parshetti, G K; Kalme, S D; Govindwar, S P


    Saccharomyces cerevisiae MTCC 463 decolourizes toxic azo dye, methyl red by degradation process. Methyl red (100mgl(-1)) is degraded completely within 16min in plain distilled water under static anoxic condition, at the room temperature. Effect of physicochemical parameters (pH of medium, composition of medium, concentration of cells, concentration of dye, temperature and agitation) on methyl red decolourization focused the optimal condition required for decolourization. Biodegradation (fate of metabolism) of methyl red in plain distilled water was found to be pH dependent. Cells of Saccharomyces cerevisiae could degrade methyl red efficiently up to 10 cycles in plain distilled water. Analysis of samples extracted with ethyl acetate from decolourized culture flasks in plain distilled water (pH 6.5) and at pH 9 using UV-VIS, TLC, HPLC and FTIR confirm biodegradation of methyl red into several different metabolites. A study of the enzymes responsible for the biodegradation of methyl red in the control and cells obtained after decolourization in plain distilled water (pH 6.5) and at pH 9 showed different levels of the activities of laccase, lignin peroxidase, NADH-DCIP reductase, azoreductase, tyrosinase and aminopyrine N-demethylase. A significant increase in the activities of lignin peroxidase and NADH-DCIP reductase was observed in the cells obtained after decolourization in plain distilled water (pH 6.5), however cells obtained at pH 9 shows increased activities of azoreductase, tyrosinase, lignin peroxidase and NADH-DCIP reductase. High efficiency to decolourize methyl red in plain distilled water and low requirement of environmental conditions enables this yeast to be used in biological treatment of industrial effluent containing azo dye, methyl red.

  18. Antimutagenic and mutagenic potentials of Chinese radish.

    PubMed Central

    Rojanapo, W; Tepsuwan, A


    The edible part of fresh Chinese radish was chopped into small pieces, lyophilized, and then extracted sequentially with hexane, chloroform, and methanol. The solvent in each fraction was removed by evaporation under reduced pressure at 50-55 degrees C, and the residue was dissolved in dimethylsufoxide just before being tested for antimutagenicity as well as mutagenicity using the Salmonella/mammalian microsome mutagenicity test. We found that none of the three fractions exhibited any mutagenicity toward S. typhimurium strains TA98 and TA100 when tested either in the presence or absence of S-9 mix. Interestingly, however, hexane and chloroform extracts could strongly inhibit the mutagenicities of both direct mutagens (e.g., 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide and sodium azide) and indirect mutagens (e.g., aflatoxin B1). In contrast, however, these two fractions did not inhibit the mutagenicity of benzo[a]pyrene, which is also an indirect mutagen. Both hexane and chloroform extracts could also markedly inhibit the activities of rat liver aniline hydroxylase and aminopyrine demethylase. The methanol fraction could inhibit neither the mutagenicities of direct or indirect mutagens tested nor the activities of those two rat liver enzymes. Results of the present study demonstrate that Chinese radish may not contain any mutagenic compound but does contain some nonpolar compounds with antimutagenic activity toward both direct and indirect mutagens. In addition, the antimutagenic activity toward aflatoxin B1 may be partly due to the inhibition of enzymes necessary for activation of this mutagen. PMID:8143625

  19. Brain mitochondrial cytochromes P450: xenobiotic metabolism, presence of multiple forms and their selective inducibility.


    Bhagwat, S V; Boyd, M R; Ravindranath, V


    The capability of rat brain mitochondria to metabolize a variety of xenobiotics was examined. The presence of cytochrome P450 (P450) and associated monooxygenase activities were estimated in isolated rat brain mitochondria and compared with the corresponding activities in microsomes. Total P450 content in brain mitochondria from naive rats was twice that of the corresponding microsomal level. The ability of brain mitochondria to metabolize the potent carcinogen N-nitrosodimethylamine was more than twofold that of the corresponding microsomal activity, while the 7-ethoxycoumarin-O-deethylase activity was significantly lower in mitochondria. Immunoblot experiments using antisera to purified rat liver microsomal P450s, namely P450 (2B1/2B2), P4501A1, and P4502E1, and purified phenobarbital-inducible rat brain P450, revealed the presence of immunoreactive bands in isolated brain mitochondria. These various antibodies to P450 inhibited the brain mitochondrial monooxygenase activities to significant, though varying extent. The addition of antiserum to microsomal NADPH cytochrome P450 reductase did not affect the mitochondrial P450 associated monooxygenase activities, although it completely inhibited the corresponding microsomal activities. Chronic ethanol administration resulted in twofold induction of total P450 content and the monooxygenase activities known to be mediated by P4502E1, such as N-nitrosodimethylamine-N-demethylase and p-nitrophenol hydroxylase in brain mitochondria. Pretreatment of animals with phenobarbital resulted in the induction of aminopyrine N-demethylase activity in brain mitochondria. The study demonstrates the presence of multiple forms of P450 in the rat brain mitochondria, their inducibility, and their capability to metabolize xenobiotics.

  20. Effects of tamoxifen and levonorgestrel treatment on carbon tetrachloride induced alterations in rats.


    Kulcsár, A; Kulcsár-Gergely, J


    Oestrogens cause progression in liver lesion, and thus ovariectomy improves hepatic injury both functionally and histologically. In the present study the efficacy of the antioestrogen tamoxifen (CAS 10540-29-1) was examined in chronical carbon tetrachloride damage. The results were compared with the effect of the progestogen levonorgestrel. Male Wistar rats were treated for 16 days. Blood sampling and autopsy were performed 2 h after last tamoxifen resp. levonorgestrel and 1 h after last CCl4 dosage. Tamoxifen diminished water content of the healthy liver. By fairly the same ratio it decreased high water content of the damaged liver. Levonorgestrel moderated water imbibition in CCl4 impairment. Tamoxifen caused protein synthesis in healthy and in injured liver. Levonorgestrel could not prevent protein loss associated with CCl4 damage. Tamoxifen counteracted, levonorgestrel moderated glycogen loss in liver lesion. Blood glucose was normal in all examined groups. Cytochrome P-450 decrease in CCl4 injury was moderated but not normalised by tamoxifen. Levonorgestrel was less effective. Cytochrome b5 content diminished in CCl4 lesion and both treatments restored it. Aminopyrine-N-demethylase was impaired by liver injury. An improvement was measured correlating with microsomal cytochrome P-450 content. This was significant with tamoxifen but not following levonorgestrel administration. The pathological serum bilirubin level of CCl4 lesion was normalised by tamoxifen as well as levonorgestrel treatment. The progestogen levonorgestrel moderated liver injury in reducing high water content, glycogen loss and normalising serum bilirubin. The antioestrogen tamoxifen seems to be a promising treatment in chronic hepatic impairment.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Isozyme-specific monoclonal antibody-directed assessment of induction of hepatic cytochrome p-450 by clotrimazole.


    Khan, W A; Kuhn, C; Merk, H F; Park, S S; Gelboin, H V; Bickers, D R; Mukhtar, H


    Clotrimazole, an N-substituted imidazole widely used as an antifungal agent, has been shown to both inhibit and induce hepatic cytochrome P-450 and related monooxygenase activities. In this study the profile of hepatic cytochrome P-450 isozyme(s) induced by clotrimazole treatment of male Sprague-Dawley rats was investigated. Clotrimazole administration (100 mg/kg, daily for 4 days, ig) resulted in 86% induction of spectrally detectable cytochrome P-450 in hepatic microsomes. In these microsomes 7-ethoxycoumarin O-deethylase (126%), aminopyrine N-demethylase (176%), benzphetamine N-demethylase (117%), p-nitrophenol hydroxylase (89%), and 7-ethoxyresorufin O-deethylase (62%) activities were significantly induced, whereas aryl hydrocarbon hydroxylase activity remained unchanged. Characterization of cytochrome P-450 isozyme(s) in hepatic microsomes prepared from clotrimazole-treated animals was based on the immunoreactivity of these microsomes with highly specific monoclonal antibodies (MAbs) raised against 3-methylcholanthrene-specific P-450 (MAb 1-7-1), phenobarbital-specific P-450 (MAb 2-66-3), pregnenolone-16 alpha-carbonitrile-specific P-450 (MAb C2), and ethanol-inducible P-450 (MAb 1-98-1). Western blot analysis of hepatic microsomes prepared from clotrimazole-treated animals with MAb 2-66-3, MAb 1-98-1, and MAb C2 revealed strong immunoreactive bands, whereas moderate reactivity was observed with MAb 1-7-1. MAb 2-66-3 significantly inhibited 7-ethoxycoumarin O-deethylase activity 45%), whereas MAb 1-7-1 moderately inhibited 7-ethoxyresorufin O-deethylase activity (-30%) in clotrimazole-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Muscarinic responses of gastric parietal cells

    SciTech Connect

    Wilkes, J.M.; Kajimura, M.; Scott, D.R.; Hersey, S.J.; Sachs, G. )


    Isolated rabbit gastric glands were used to study the nature of the muscarinic cholinergic responses of parietal cells. Carbachol stimulation of acid secretion, as measured by the accumulation of aminopyrine, was inhibited by the M1 antagonist, pirenzepine, with an IC50 of 13 microM; by the M2 antagonist, 11,2-(diethylamino)methyl-1 piperidinyl acetyl-5,11-dihydro-6H-pyrido 2,3-b 1,4 benzodiazepin-6-one (AF-DX 116), with an IC50 of 110 microM; and by the M1/M3 antagonist, diphenyl-acetoxy-4-methylpiperidinemethiodide, with an IC50 of 35 nM. The three antagonists displayed equivalent IC50 values for the inhibition of carbachol-stimulated production of 14CO2 from radiolabeled glucose, which is a measure of the turnover of the H,K-ATPase, the final step of acid secretion. Intracellular calcium levels were measured in gastric glands loaded with FURA 2. Carbachol was shown to both release calcium from an intracellular pool and to promote calcium entry across the plasma membrane. The calcium entry was inhibitable by 20 microM La3+. The relative potency of the three muscarinic antagonists for inhibition of calcium entry was essentially the same as for inhibition of acid secretion or pump related glucose oxidation. Image analysis of the glands showed the effects of carbachol, and of the antagonists, on intracellular calcium were occurring largely in the parietal cell. The rise in cell calcium due to release of calcium from intracellular stores was inhibited by 4-DAMP with an IC50 of 1.7 nM, suggesting that the release pathway was regulated by a low affinity M3 muscarinic receptor or state; Ca entry and acid secretion are regulated by a high affinity M3 muscarinic receptor or state, inhibited by higher 4-DAMP concentrations, suggesting that it is the steady-state elevation of Ca that is related to parietal cell function rather than the (Ca)i transient.

  3. Hepatic arachidonic acid metabolism is disrupted after hexachlorobenzene treatment.


    Billi de Catabbi, Silvia C; Faletti, Alicia; Fuentes, Federico; San Martín de Viale, Leonor C; Cochón, Adriana C


    Hexaclorobenzene (HCB), one of the most persistent environmental pollutants, can cause a wide range of toxic effects including cancer in animals, and hepatotoxicity and porphyria both in humans and animals. In the present study, liver microsomal cytochrome P450 (CYP)-dependent arachidonic acid (AA) metabolism, hepatic PGE production, and cytosolic phospholipase A2 (cPLA2) activity were investigated in an experimental model of porphyria cutanea tarda induced by HCB. Female Wistar rats were treated with a single daily dose of HCB (100 mg kg(-1) body weight) for 5 days and were sacrificed 3, 10, 17, and 52 days after the last dose. HCB treatment induced the accumulation of hepatic porphyrins from day 17 and increased the activities of liver ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and aminopyrine N-demethylase (APND) from day 3 after the last dose. Liver microsomes from control and HCB-treated rats generated, in the presence of NADPH, hydroxyeicosatetraenoic acids (HETEs), epoxyeicosatrienoic acids (EETs), 11,12-Di HETE, and omega-OH/omega-1-OH AA. HCB treatment caused an increase in total NADPH CYP-dependent AA metabolism, with a higher response at 3 days after the last HCB dose than at the other time points studied. In addition, HCB treatment markedly enhanced PGE production and release in liver slices. This HCB effect was time dependent and reached its highest level after 10 days. At this time cPLA2 activity was shown to be increased. Unexpectedly, HCB produced a significant decrease in cPLA2 activity on the 17th and 52nd day. Our results demonstrated for the first time that HCB induces both the cyclooxygenase and CYP-dependent AA metabolism. The effects of HCB on AA metabolism were previous to the onset of a marked porphyria and might contribute to different aspects of HCB-induced liver toxicity such as alterations of membrane fluidity and membrane-bound protein function. Observations also suggested that a possible role of cPLA2

  4. Glycine-extended progastrin processing intermediates induce H+,K(+)-ATPase alpha-subunit gene expression through a novel receptor.


    Kaise, M; Muraoka, A; Seva, C; Takeda, H; Dickinson, C J; Yamada, T


    Biologically active amidated gastrin is synthesized by carboxyl-terminal alpha-amidation of a glycine-extended progastrin post-translational processing intermediate (G-Gly). Although plasma levels of G-Gly are equivalent to those of gastrin, G-Gly has essentially no acute effect on gastric acid secretion. However, we have observed that inhibition of gastrin amidation leads to increased plasma concentrations of G-Gly and enhanced gastric acid secretion. We hypothesized, therefore, that G-Gly might have a chronic effect to increase H+,K(+)-ATPase expression in gastric parietal cells. In the present studies, we observed that a 2-day preincubation with G-Gly significantly enhanced histamine-stimulated [14C]aminopyrine uptake by isolated canine gastric parietal cells but acutely administered G-Gly had no effect. On Northern blot analysis, both G-Gly and gastrin dose-dependently increased H+,K(+)-ATPase alpha-subunit gene expression with maximal induction (225 +/- 35 and 170 +/- 29% of basal, mean +/- S.E.) achieved at concentrations of 10(-9) M G-Gly and 10(-8) M gastrin, respectively. Using an H+,K(+)-ATPase alpha-subunit gene-luciferase chimeric reporter construct transfected into primary cultured parietal cells, we observed that both G-Gly and gastrin increased luciferase activity in a manner similar to that obtained by Northern blot analysis. L365,260, a specific gastrin/CCKB receptor antagonist, completely reversed the stimulation of luciferase activity induced by gastrin but had no effect on G-Gly-stimulated activity. Gastrin increased [Ca2+]i, although G-Gly did not, however, genistein (a tyrosine kinase inhibitor) significantly reduced induction of luciferase activity by both G-Gly and gastrin. Specific binding of 125I-Leu15-G2-17-Gly to gastric parietal cells was dose-dependently displaced by G2-17-Gly but not by gastrin nor L365,260. Gastrin peptides truncated at the carboxyl- (G1-13) and amino terminus (G5-17-Gly) both induced H+,K(+)-ATPase alpha

  5. Effect of the degree of hydrogenation of fish oil on the enzymatic activity and on the fatty acid composition of hepatic microsomes from young and aged rats.


    Morgado, Nora; Sanhueza, Julio; Nieto, Susana; Valenzuela, Alfonso


    By modifying the degree of hydrogenation of dietary fat, it is possible to modify the fatty acid composition and the biochemical activity of cellular tissues. The age can be another variable influencing these modifications. The effect of isocaloric diets containing oils with different degrees of hydrogenation: fish oil (FO, 0.3% TRANS), partially hydrogenated fish oil (PHFO, 29% TRANS), or highly hydrogenated fish oil (HHFO, 2.3% TRANS), in the fatty acid composition (CIS and TRANS isomers) of hepatic microsomes from young (70-day-old) and aged (18-month-old) rats, in the microsomal cytochrome P-450 (C-450) content, and in the aminopyrine N-demethylase (AND), aniline hydroxylase (AH), NADPH cytochrome P-450 reductase (NCR), UDP-glucuronyl transferase (UGT), and GSH-S transferase (GST) enzymatic activities were studied. Fatty acid composition and n-6/n-3 ratio of microsomal membranes was modified to a higher extent in young rats. C-450 content and AND activity were reduced when the degree of hydrogenation of dietary fat was increased in the young and the aged rats. AH activity was higher after the PHFO diet in the young rats only. NCR activity was reduced in the young animals when the hydrogenation of the fat was increased. However, in aged rats the enzyme exhibited a higher activity after the PHFO and HHFO diet. UGT and GST activities where not affected by the level of hydrogenation of the dietary fat in both the young and the aged rats. However, UGT activity was higher in the young rats, while GST activity was higher in the aged animals. We conclude that hydrogenation of dietary fat can modify the fatty acid composition of hepatic microsomes, young animals being more sensitive to these changes than aged animals. These effects were also reflected in the amount and/or the activity of some molecular components of the hepatic microsomal mixed-function oxidase enzyme system. Microsomal TRANS fatty acid composition is not affecting the activity of the enzymes, the age

  6. Xenobiotics in gametes of Lake Michigan lake trout (Salvelinus namaycush) induce hepatic monooxygenase activity in their offspring.


    Binder, R L; Lech, J J


    Eggs spawned from Lake Michigan lake trout contain a number of xenobiotic compounds, including polychlorinated biphenyls (PCBs). To assess whether this contamination is sufficient to induce hepatic cytochrome P-450-dependent monooxygenase (MO) activity during early development, the hepatic MO systems of laboratory-cultured offspring of Lake Michigan, Green Bay, and Marquette Hatchery lake trout were compared. Additionally, the induction of hepatic cytochrome P-450 systems in developing lake trout by the commercial PCB mixture, Aroclor 1254 (A1254), was characterized. During late embryonic development and at the swim-up stage, the hepatic MO systems of the feral lake trout offspring appeared induced, based on levels of aryl hydrocarbon hydroxylase (AHH) activity that were 3.5- to 8.6-fold higher than the hatchery control levels. Furthermore, at the swim-up stage the feral trout offspring resembled A1254-treated hatchery fry with regard to the degree of inhibition of hepatic AHH activity by alpha-naphthoflavone, and the presence of an inducible Mr = 58,000 polypeptide in hepatic microsomes. The levels of aminopyrine N-demethylase activity, which was relatively unresponsive to inducers, were moderately lower in the Lake Michigan and Green Bay swim-up fry compared to the hatchery control levels. After 7 months of posthatching laboratory culture, when residues of xenobiotics present at fertilization were greatly diluted by growth, the hepatic MO systems of the Lake Michigan and hatchery trout offspring appeared essentially indistinguishable with regard to a number of parameters. These results indicate that the differences observed between the hatchery and feral trout offspring at earlier stages were not likely to have a genetic basis, but rather were due to a xenobiotic-type induction. Dose-response experiments and residue analysis data indicated that residues of commercial PCB mixtures were at least partially responsible for the effects described here. Overall, these

  7. Effect of a single administration of benzene, toluene or m-xylene on carboxyhaemoglobin elevation and metabolism of dichloromethane in rats.


    Kim, S K; Kim, Y C


    The effect of a single administration of aromatic hydrocarbons (AHCs) on the metabolic activity responsible for the biotransformation of dichloromethane (DCM) to carbon monoxide (CO) was investigated using adult female rats. In rats treated orally with benzene (1.5 ml kg-1), toluene (2.0 ml kg-1) or m-xylene (2.0 ml kg-1) 16-24 h prior to DCM (3 mmol kg-1, i.p.), the carboxyhaemoglobin (COHb) level was elevated, reaching peaks in blood at 21%, 16% and 23%, respectively, compared to the peak of ca. 10% in rats treated with DCM only. Their effects on COHb generation were highly dependent on the time interval between each AHC and DCM treatment, since an early administration of m-xylene or toluene decreased the COHb elevation. The half-life of DCM in blood was shortened significantly, indicating that the metabolic degradation of DCM was enhanced by the AHCs. Disulfiram (3.4 mmol kg-1, p.o.) blocked COHb elevation completely, suggesting that the metabolic conversion of DCM to CO is mediated by cytochrome P-450 2E1 (P4502E1). Corresponding increases in the concentration and half-life of DCM in blood were also observed. A single administration of the AHCs did not alter the hepatic glutathione level, suggesting that the increase in DCM-induced COHb elevation was not due to hepatic glutathione depletion. In vitro studies showed that the hepatic microsomal metabolism of nitrosodimethylamine and p-nitrophenol was significantly increased by a single dose of each AHC. Total cytochrome P-450 content and p-nitroanisole demethylase activity were also increased; however, only toluene and m-xylene were effective inducers for aminopyrine N-demethylase. Therefore, benzene appears to be a selective inducer for P4502E1 compared to other alkylbenzenes. The results indicate that even a single dose of benzene, toluene or m-xylene may induce the activity of P4502E1 significantly, which is responsible for the increased generation of COHb from DCM, as demonstrated in the present study.

  8. The physiological background behind and course of development of the first proton pump inhibitor.


    Lundell, Lars


    Gastric acid secretion and its related diseases and their treatments have generated important contributions to gastroenterology and its development as an autonomous medical specialty. The discovery of histamine receptors and the subsequent H2-receptor antagonists (1972) changed the practice of gastroenterology forever. Gastric acid was effectively inhibited and ulcers could be healed to an extent which had not previously been seen. An additional milestone along the same avenue was offered by the identification of hydrogen potassium adenosine triphosphatase (H(+)K(+)-ATPase) as the proton pump of the parietal cell. Nowadays, proton pump inhibitors (PPIs) are widely used. However, we need to reconsider the physiology and pathophysiology of acid secretion and its long-term inhibition to avoid potential negative effects on general health. PPIs are generally considered among the safest class of drugs. In the late 1960s, a research project was initiated to develop an antisecretory drug which could be used in acid hypersecretory disease states such as peptic ulcer disease based on the option to synthesize a local anesthetic drug that could be orally administered and therefore have its main action on the gastrin cells. This concept was soon found to be a blind track and further development of the basic compounds CMN131 by the synthesis of H77/67 were found to be active in the gastric acid secretion, and the benzimidazol analog of H77/67 was then synthesized a year later and was tested and found to exert powerful acid inhibitory effects. Binding studies with the substituted benzimidazoles clarified specific binding to H+/K+/ATPase in the secretory vesicles of the parietal cells. Since weak bases like aminopyrine accumulate in the acid compartment of the parietal cells, the chemists changed the substituents of the heterocyclic ring and obtained a compound with a weak base property with an optimal PkA value, thereby maximizing the accumulation of the compound at the site of

  9. Inhibition of cytochrome p450 enzymes by enrofloxacin in the sea bass (Dicentrarchus labrax).


    Vaccaro, E; Giorgi, M; Longo, V; Mengozzi, G; Gervasi, P G


    Currently, there are no reports on the effects of enrofloxacin (EF), a fluoroquinolone antibiotic, on the cytochrome p450 enzymes in fish, although its use as antimicrobial agent in aquaculture has been put forward. Therefore, the in vivo and in vitro effects of EF on hepatic p450 enzymes of sea bass, a widespread food-producing fish, have been evaluated. Sea bass pretreated with a single dose of EF (3 mg/kg i.p.) or with three daily doses of EF (1 mg/kg i.p.) markedly depressed the microsomal N-demethylation of aminopyrine, erythromycin, the O-deethylation of 7-ethoxycoumarin, ethoxyresorufin and the 6beta-testosterone hydroxylase. In vitro experiments showed that EF at 10 microM inhibited the above-mentioned activities and, in particular, the erythromycin N-demethylase (ERND) and 6beta-testosterone-hydroxylase, likely dependant on a p450 3A isoform. When the nature of ERND inhibition by EF was specifically studied with sea bass liver microsomes, it was found that EF is a potent mechanism-based inhibitor, with K(i) of 3.7 microM and a K(inact) of 0.045 min(-1). An immunoblot analysis with anti p450 3A27 of trout showed that the p450 3A isoform, constitutively expressed in sea bass, is particularly susceptible to inactivation by EF. In vitro experiments with sea bass microsomes have also demonstrated that EF is oxidative deethylated by the p450 system to ciprofloxacin (CF) and that this compound maintains the ability to inactivate the p450 enzymes. The mechanism by which EF or CF inactivate the p450 enzymes has not been studied but an attack of p450 on the cyclopropan ring, present, both in EF and CF structure, with the formation of electrophilic intermediates (i.e. radicals) has been postulated. In conclusion, the EF seems to be a powerful inhibitor of p450s in the sea bass. Therefore, the clinical use of this antibiotic in aquaculture has to be considered with caution.

  10. Gene response of CYP360A, CYP314, and GST and whole-organism changes in Daphnia magna exposed to ibuprofen.


    Wang, Lan; Peng, Ying; Nie, Xiangping; Pan, Benben; Ku, Peijia; Bao, Shuang


    The fate and ecological impact of non-steroidal anti-inflammatory drugs (NSAIDs) in aquatic environments has gained increasingly concern recently. However, limited information is provided about the toxicity mechanism of NSAIDs to aquatic invertebrates. In the present study, we investigated the expression of CYP360A, CYP314, and GST genes involved in the detoxification process and the responses of their associated enzymes activity, as well as whole-organism changes in Daphnia magna exposed to environmentally relevant concentrations of ibuprofen (IBU). Results showed that the total amount of eggs produced per female, total number of brood per female, and body length were significantly decreased under IBU exposure, suggesting the effects of chronic IBU exposure on growth and reproduction of D. magna cannot be ignored. In gene expression level, the CYP360A gene, homologue to CYP3A in mammalian, showed inhibition at low concentration of IBU (0.5μg·L(-1)) and induction at high concentration of IBU (50μg·L(-1)). GST gene also exhibited a similar performance to CYP3A. CYP314 displayed inhibition for short time exposure (6h) and induced with prolonged exposure time (48h) at low concentration of IBU (0.5μg·L(-1)). Erythromycin N-demethylase (ERND) and aminopyrine N-demethylase (APND) related to cytochrome oxidase P450 (CYPs) were inhibited for short time exposure (6h) to IBU and then activated with prolonged exposure time (48h) at low concentration of IBU (0.5μg·L(-1)), while EROD showed a dose-dependent pattern under IBU exposure. As for antioxidative system, induction of glutathione S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) was observed in short-term exposure to IBU. Meanwhile, methane dicarboxylic aldehyde (MDA) content increased with the increasing IBU concentration and the delayed exposure time, displaying obvious dose- and time-dependent pattern. In summary, IBU significantly altered some physiological and biochemical parameters and

  11. Cytochromes P450 (CYP) in tropical fishes: catalytic activities, expression of multiple CYP proteins and high levels of microsomal P450 in liver of fishes from Bermuda.


    Stegeman, J J; Woodin, B R; Singh, H; Oleksiak, M F; Celander, M


    Hepatic microsomes prepared from 10 fish species from Bermuda were studied to establish features of cytochrome P450 (CYP) systems in tropical marine fish. The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 and 0.25 nmol/mg. Ethoxycoumarin O-deethylase (ECOD) and aminopyrine N-demethylase (APND) rates in these 7 species were 0.23-2.1 nmol/min/mg and 0.5-11 nmol/min/mg, respectively, similar to rates in many temperate fish species. In contrast to those 7 species, sergeant major (Abudefduf saxatilis) and Bermuda chub (Kyphosus sectatrix) had microsomal P450 contents near 1.7 nmol/mg, among the highest values reported in untreated fish, and had greater rates of ECOD, APND, ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-depentylase than did most of the other species. Freshly caught individuals of all species had detectable levels of EROD and aryl hydrocarbon hydroxylase (AHH) activities. Those individuals with higher rates of EROD activity had greater content of immunodetected CYP1A protein, consistent with Ah-receptor agonists acting to induce CYP1A in many fish in Bermuda waters. Injection of tomtate and blue-striped grunt with beta-naphthoflavone (BNF; 50 or 100 mg/kg) induced EROD rates by 25 to 55-fold, suggesting that environmental induction in some fish was slight compared with the capacity to respond. AHH rates were induced only 3-fold in these same fish. The basis for disparity in the degree of EROD and AHH induction is not known. Rates of APND and testosterone 6 beta- and 16 beta-hydroxylase were little changed by BNF, indicating that these are not CYP1A activities in these fish. Antibodies to phenobarbital-inducible rat CYP2B1 or to scup P450B, a putative CYP2B, detected one or more proteins in several species, suggesting that CYP2B-like proteins are highly expressed in some tropical fishes. Generally, species with greater amounts of total P450 had greater amounts of

  12. Amended final report of the safety assessment of Drometrizole as used in cosmetics.



    Drometrizole is used in cosmetics as an ultraviolet (UV) light absorber and stabilizer. In an earlier safety assessment, the available data were found insufficient to support the safety of this ingredient, but new data have been provided and assessed. In voluntary industry reports to the Food and Drug Administration, this ingredient is reported to be used in noncoloring hair care products, and in an industry use concentration survey, uses in nail care products at 0.07% were reported. Drometrizole has absorbance maxima at 243, 298, and 340 nm. Drometrizole is used widely as a UV absorber and stabilizer in plastics, polyesters, celluloses, acrylates, dyes, rubber, synthetic and natural fibers, waxes, detergent solutions, and orthodontic adhesives. It is similarly used in agricultural products and insecticides. Drometrizole is approved as an indirect food additive for use as an antioxidant and/or stabilizer in polymers. Short-term studies using rats reported liver weight increases, increases in the activities of enzymes aminopyrine N-demethylase, and UDP glucuronosyl transferase, but no significant effects were noted in the activities of acid hydrolases or in hepatocyte organelles. Although Drometrizole is insoluble in water and soluble in a wide range of organic solvents, a distribution and elimination study using rats indicated that some Drometrizole was absorbed, then metabolized and excreted in the urine. Drometrizole and products containing Drometrizole were nontoxic in acute oral, inhalation, and dermal studies using animals. No increase in mortality or local and/or systemic toxicity were observed in a 13-week oral toxicity study using dogs; the no observed effect level (NOEL) was 31.75 mg/kg day(- 1) for males and 34.6 mg/kg day(-1) for females. In a 2-year feeding study using rats, a NOEL of 47 to 58 mg/kg day(- 1) was reported. Developmental studies of Drometrizole in rats and mice found no teratogenic effects and a NOEL of 1000 mg/kg day(- 1) was reported