ethylmorphine and aniline

Extracts of the adult worms of both Schistosoma mansoni and Schistosoma haematobium can metabolise some typical P450 substrates but to differing degrees. S. mansoni worm extracts displayed a approximately 12-fold higher specific activity for an aminopyrine substrate than rat liver microsomes. At 4 mM substrate concentration the demethylation reaction with N-nitrosodimethylamine (NDMA) (5 nmol HCHO/mg protein/min) was only half that of rat liver microsomes, whereas in extracts of S. haematobium, no detectable activity was found towards NDMA. Using ethylmorphine as substrate the demethylation activity of S. mansoni extracts (1.82 nmol HCHO/mg protein/min) was 5.5-fold lower than that of rat liver microsomes. Benzphetamine demethylase activity was also readily detectable in S. mansoni worm extracts at 6.79 nmol HCHO/mg protein/min compared with 10.20 nmol HCHO/mg protein/min in the case of rat liver microsomes. When aniline was used as substrate, surprisingly, no activity was found in worm extracts of either S. mansoni or S. haematobium, whereas rat liver microsomes showed high activity towards this amine. The anti-P450 2E1 and 2B1/2 cross-reacted with both worm homogenates and gave a specific band corresponding to a protein of molecular weight of approximately 50.0 kDa. A study with anti-P450 IVA antibody revealed that while this protein was strongly expressed in S. haematobium worm extracts, no immunoreactivity was observed with extracts of S. mansoni. Immunoblotting analyses with anti-P450 IIIA and P450 1A1 did not detect immunoreactive protein in either S. mansoni or S. haematobium.

Topics: Aminopyrine; Aniline Compounds; Animals; Benzphetamine; Cricetinae; Cytochrome P-450 Enzyme System; Dimethylnitrosamine; Enzyme Activation; Ethylmorphine; Female; Formaldehyde; Immunoblotting; Male; Mice; Microsomes, Liver; NADPH-Ferrihemoprotein Reductase; Oxazines; Rats; Schistosoma haematobium; Schistosoma mansoni; Substrate Specificity

Levels of cytochrome P450 (P450 or CYP) proteins immunoreactive to antibodies raised against human CYP1A2, 2A6, 2C9, 2E1, and 3A4, monkey CYP2B17, and rat CYP2D1 were determined in liver microsomes of rats, guinea pigs, dogs, monkeys, and humans. We also examined several drug oxidation activities catalyzed by liver microsomes of these animal species using eleven P450 substrates such as phenacetin, coumarin, pentoxyresorufin, phenytoin, S-mephenytoin, bufuralol, aniline, benzphetamine, ethylmorphine, erythromycin, and nifedipine; the activities were compared with the levels of individual P450 enzymes. Monkey liver P450 proteins were found to have relatively similar immunochemical properties by immunoblotting analysis to the human enzymes, which belong to the same P450 gene families. Mean catalytic activities (on basis of mg microsomal protein) of P450-dependent drug oxidations with eleven substrates were higher in liver microsomes of monkeys than of humans, except that humans showed much higher activities for aniline p-hydroxylation than those catalyzed by monkeys. However, when the catalytic activities of liver microsomes of monkeys and humans were compared on the basis of nmol of P450, both species gave relatively similar rates towards the oxidation of phenacetin, coumarin, pentoxyresorufin, phenytoin, mephenytoin, benzphetamine, ethylmorphine, erythromycin, and nifedipine, while the aniline p-hydroxylation was higher and bufuralol 1'-hydroxylation was lower in humans than monkeys. On the other hand, the immunochemical properties of P450 proteins and the activities of P450-dependent drug oxidation reactions in dogs, guinea pigs, and rats were somewhat different from those of monkeys and humans; the differences in these animal species varied with the P450 enzymes examined and the substrates used. The results presented in this study provide useful information towards species-related differences in susceptibilities of various animal species regarding actions and toxicities of drugs and xenobiotic chemicals.

Topics: Adrenergic beta-Antagonists; Aniline Compounds; Animals; Antineoplastic Agents; Benzphetamine; Carcinogens; Coumarins; Cytochrome P-450 Enzyme System; Dogs; Erythromycin; Ethanolamines; Ethylmorphine; Guinea Pigs; Humans; Macaca fascicularis; Mephenytoin; Microsomes, Liver; Nifedipine; Oxazines; Oxidation-Reduction; Phenacetin; Phenytoin; Rats; Species Specificity

1. Colupulone, a constituent of hops, was shown to be a potent inducer of hepatic P4503A in mouse. The olefin, 2-methyl-3-buten-2-ol (RC = CH2), is formed from lupulones when hops are exposed to atmospheric hydroxyl radicals. This suggested the possibility that the same reaction may occur in vivo. The credibility of this hypothesis was enhanced when RC = CH2 was shown to induce P4503A in mouse. Ethylmorphine (EM) N-demethylation, a functional marker for P4503A, was also induced by RC = CH2. 2. 3-Methyl-1-pentyn-3-ol (RC identical to meparfynol), a sedative and close structural analogue of RC = CH2, also induced P4503A and EM N-demeythylation. Tert-amyl alcohol (RC-CH3), the saturated analogue of RC = CH2, was included in t he study with the expectation that it would serve as a negative control for the anticipated induction of P4503A by the other two alcohols. This proved not to be the case; RC-CH3 was about as active an inducer of P4503A as RC = CH2 and RC identical to CH. The possibility is considered that, like valproic acid, RC-CH3 is metabolized to an olefin by P450. 3. Hydroxylation of aniline and benzo[a]pyrene by hepatic microsomes from mice treated with the three alcohols were used as functional markers for the induction of P4502E and P4501A respectively. RC = CH2 at the two lowest levels of administration suppressed aniline hydroxylation but had no effect at the highest level. RC identical to CH was ineffective and RC-CH3 was moderately inductive at all three levels. Each of the three compounds were weak to moderate inducers of benzo[a]pyrene hydroxylation.

Topics: Aniline Compounds; Animals; Blotting, Western; Cyclohexanones; Ethylmorphine; Hydroxylation; Male; Methylation; Mice; Pentanols

Experiments were conducted to examine the effect of manganese on the hepatic mixed function oxidase system in the rat. Acute treatment with manganese chloride (1-10 mg Mn/kg, ip) produced a significant prolongation of hexobarbital hypnosis in male rats on Days 2 and 3 following metal administration. The threshold dose of manganese to produce this alteration in response was 5 mg Mn/kg and the altered response returned to control values by Day 5. The prolonged hexobarbital hypnosis resulted from Mn inhibition of the hepatic microsomal mixed function oxidase system, the activity of which was assessed using aniline (23%), ethylmorphine (26%), and hexobarbital (27%) as substrates. Manganese treatment also produced significantly reduced levels of cytochrome P-450 (23%) and b5 (21%), but the substrate-induced spectral binding of all three substrates was not altered significantly by Mn when expressed as delta A per nanomole of cytochrome P-450. The activity of NADPH cytochrome c reductase was also significantly decreased (25%) by Mn treatment. Following the in vitro addition of Mn in concentrations ranging from 1 X 10(-6) to 1 X 10(-3) M Mn to microsomes derived from naive rats, there was no decrease in the metabolism of aniline or hexobarbital or cytochrome P-450 levels. Significant inhibition in ethylmorphine metabolism was observed with Mn concentrations of 1 X 10(-4) M and greater. These experiments indicate that acute Mn treatment can alter drug response as the result of decreased hepatic biotransformation which occurs by an indirect mechanism.

Topics: Aniline Compounds; Animals; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Ethylmorphine; Hexobarbital; Hypnosis; In Vitro Techniques; Male; Manganese Poisoning; Microsomes, Liver; Mixed Function Oxygenases; Rats; Rats, Inbred Strains

The role of the pituitary gland in the effects of treatment with phenobarbital, methylcholanthrene and morphine on hepatic drug metabolism in adult male and adult female rats has been investigated. A marked sex difference in the effects of treatment with these three compounds on hepatic drug metabolizing enzymes in intact adult rats was observed. No sex differences in the effects of phenobarbital methylcholanthrene or morphine on hepatic drug metabolizing enzymes were observed after treatment of hypophysectomized adult male and hypophysectomized adult female rats. The results indicate that the pituitary gland plays an important role in the determination of sex differences in the response of hepatic drug metabolizing enzymes to inducing agents.

Topics: Aniline Compounds; Animals; Chromatography, Gas; Epoxy Compounds; Ethylmorphine; Female; Hypophysectomy; Male; Methylcholanthrene; Microsomes, Liver; Morphine; Phenobarbital; Rats; Rats, Inbred Strains; Sex Characteristics

Hepatic microsomal drug metabolism was assessed in male and female rats, mice and hamsters 72 hr after administration of sodium selenite. The greatest inhibitory effect of selenium on hepatic drug metabolism occurred in male rats where the magnitude of reduction in microsomal metabolism by selenium treatment of ethylmorphine and aminopyrine was disproportionately greater than the decrease in either cytochrome P-450 levels or metabolism of aniline. In contrast, the inhibition of metabolism of the three substrates in female mice and the decrease in ethylmorphine-N-demethylase in male mice were similar in magnitude to the reduction observed in cytochrome P-450 content. Hepatic microsomal metabolism in male and female hamsters was relatively resistant to the inhibitory effects of selenium. The inhibition of drug metabolism by selenium may reflect a specific effect of selenium on selected isozymes of cytochrome P-450.

Topics: Aminopyrine; Aniline Compounds; Animals; Biotransformation; Cricetinae; Cytochrome P-450 Enzyme System; Ethylmorphine; Female; Male; Mesocricetus; Mice; Microsomes, Liver; Rats; Rats, Inbred Strains; Selenium; Sex Factors; Species Specificity

Pretreatment of male rats with phenobarbital markedly depressed the duration of pentobarbital hypnosis and stimulated the hepatic microsomal metabolism of ethylmorphine and aniline. Following selenium treatment there was a prolongation of pentobarbital hypnosis and an inhibition of metabolism of ethylmorphine with no effect on that of aniline. When phenobarbital and selenium were administered simultaneously, the opposing effects on the duration of pentobarbital hypnosis cancelled each other. With respect of hepatic metabolism, differential effects were observed with the inhibitory effect elicited by selenium on ethylmorphine metabolism being prevented by phenobarbital. However, selenium enhanced the stimulatory effect elicited by phenobarbital on aniline metabolism.

Topics: Aniline Compounds; Animals; Drug Interactions; Ethylmorphine; Male; Microsomes, Liver; Pharmaceutical Preparations; Phenobarbital; Rats; Rats, Inbred Strains; Selenium