Liver Smooth Endoplasmic Reticulum “Microsomal” Drug-Metabolizing Enzyme System

Fouts, James R.

doi:10.1007/978-1-4615-7425-5_9

Cited by 27 publications

(9 citation statements)

References 36 publications

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“…Increases in hexobarbital sleeping time, an index o f in vivo hepatic microsomal drug me tabolism in most cases (25,26). correlated well with the reduction in the cytochrome P-450 levels in vitamin A deficiency.…”

Section: Discussionmentioning

confidence: 78%

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Hepatic Cytochrome P-450-Dependent Metabolism and Enzymatic Conjugation of Foreign Compounds in Vitamin A-Deficient Rats

Siddik¹,

Drew²,

Litterst³

et al. 1980

Pharmacology

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The temporal effects of vitamin A deficiency on hepatic cytochrome P-450-de pendent and conjugation reactions were studied in the rat. Cytochrome P-450 levels and N-methyl-p-chloroaniline N-demethylase activity were significantly reduced in the deficient animals. No other changes in parameters dependent on cytochrome P-450 were observed in vitro. Decreases in hepatic cytochrome P450 were accompanied by a prolongation in hexobarbital sleeping times in deficient animals. The p-aminobenzoic acid N-acetyltransferase activity was higher in the deficient animals at 8 weeks, but by 10 weeks the activity in fact was significantly lower as compared to controls. Activities of ‘native’ and UDP N-acetylglucosamine ‘activated’ UDP-glucuronyltransferase were reduced in vitamin A deficiency. In contrast to this general pattern of impaired drug metabolism in vitamin A deficiency, glutathione S-aryltransferase activity was markedly enhanced at all time points from 4 to 10 weeks. Activities of this enzyme were twice controls at 6 weeks, a time at which no other enzyme changes were observed.

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Section: Discussionmentioning

confidence: 78%

“…Hexobarbital sleeping time correlates well with the rate o f metabolism o f hexobarbital by the hepatic cytochrome P-450-dependent enzyme system (25,26). This parameter, therefore was used in the present study to assess in vivo hepatic MFO activity.…”

Section: Resultsmentioning

confidence: 99%

Hepatic Cytochrome P-450-Dependent Metabolism and Enzymatic Conjugation of Foreign Compounds in Vitamin A-Deficient Rats

Siddik¹,

Drew²,

Litterst³

et al. 1980

Pharmacology

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“…Perhaps, we were able to produce an androgenic response in the Tfm mouse because we administered testosterone for 14 days as compared to 6 days by Brown et al,(1 978b). It has been reported (Fouts, 1971) that two to four weeks of treatment with anabolic steriods seems to be required to produce maximal stimulation of hepatic microsomal enzymes in some rodents. In this regard, the activity of hepatic microsomal ethylmorphine demethylation was increased in Tfm rats treated with testosterone for 33 days (Bullock et al, 1971).…”

Section: Tfm Micementioning

confidence: 99%

SEXUAL DIMORPHISM AND THE EFFECTS OF THE X‐LINKED Tfm LOCUS ON HEXOBARBITONE METABOLISM AND ACTION IN MICE

King

Shapiro

1981

British J Pharmacology

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1 Normal males of the testicular feminized strain of mice (Tfm) had longer hexobarbitone-induced sleeping times than females, and hepatic hexobarbitone hydroxylase activity differed in that the Km was higher and the V,,, lower in the male. 2 Castration and androgen replacement studies indicated that testicular androgens were responsible for the sexual differences in drug metabolism found in this mouse strain. 3 Hepatic hexobarbitone metabolism and action were feminized in the intact, androgeninsensitive, genetically male Tfm mouse. Furthermore, hexobarbitone hydroxylase activities were less responsive to large doses of testosterone in Tfm mice than in normal males. 4 The Tfm mouse with a deficiency in androgen receptors responded to the enzyme-inductive effects of phenobarbitone and softwood bedding, indicating that these inducers do not act through the androgen receptors.

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“…Our biochemical results are substantiated by the PCNor ACTH-induced hepatic ultrastructural changes, especially those affecting the ER. The increase in SER of hepatocytes is usually associated with enhanced activity of hepatic drugmetabolizing enzymes (Fouts, 1962;Remmer & Merker, 1963;Fouts & Rogers, 1965;Fouts, 1971). However, the increase in the number of lipid droplets in PCN-and especially in PCN + ACTH -treated rats-is not adequately understood.…”

Section: Discussionmentioning

confidence: 99%

Effect of ACTH, corticoids and PCN (pregnenolone-16α-carbonitrile) on drug responses and disposition

Szabó¹

1979

Acta Endocrinologica

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The endocrine system plays an important role in the adaptation of the organism to environmental stimuli: it influences both specific and nonspecific responses. The ,,emergency reaction" and the ,,stress syndrome" were recognized a long time ago, but they remain very complex processes. Elucidation of their mechanism(s) of action is difficult, and the importance of individual hormones is not yet clearly understood. extracts and corticosterone, but not by DOC (Jensen & Grattan, 1940).

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Liver Smooth Endoplasmic Reticulum “Microsomal” Drug-Metabolizing Enzyme System

Cited by 27 publications

References 36 publications

Hepatic Cytochrome P-450-Dependent Metabolism and Enzymatic Conjugation of Foreign Compounds in Vitamin A-Deficient Rats

Hepatic Cytochrome P-450-Dependent Metabolism and Enzymatic Conjugation of Foreign Compounds in Vitamin A-Deficient Rats

SEXUAL DIMORPHISM AND THE EFFECTS OF THE X‐LINKED Tfm LOCUS ON HEXOBARBITONE METABOLISM AND ACTION IN MICE

Effect of ACTH, corticoids and PCN (pregnenolone-16α-carbonitrile) on drug responses and disposition

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