Effect of vitamin A deficiency on hepatic and intestinal drug metabolizing enzymes in rats.
Feeding of vitamin A-deficient diet to male weanling rats for 10 weeks caused significant reduction in the hepatic cytochrome P-450, cytochrome b5, aminopyrine N-demethylase and arylhydrocarbon hydroxylase activities. Contrary to this, the levels of these Phase I enzymes were found to be significantly elevated in all the 3 portions (proximal, middle and distal) of the intestine in deficient animals as compared to corresponding pair-fed controls. Of the Phase II enzymes studied, UDP-glucuronyltransferase showed a significant decrease whereas glutathione S-transferase showed a significant increase in vitamin A-deficient rat liver and small intestine. The study suggests that vitamin A deficiency causes an imbalance between the Phase I and phase II drug metabolizing enzyme systems which may decrease the capacity of the organism to withstand the neoplastic effects of chemical carcinogens in vitamin A deficiency.
Gupta
P H
PH
Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Mehta
S
S
Mehta
S K
SK
D000633:Aminopyrine N-Demethylase / Q000378:metabolism; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003573:Cytochrome b Group / Q000378:metabolism; D015786:Cytochromes b5; D014453:Glucuronosyltransferase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007422:Intestines / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014802:Vitamin A Deficiency / Q000201:enzymology*
D003573:Cytochrome b Group; D004364:Pharmaceutical Preparations; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; D000633:Aminopyrine N-Demethylase; D009251:NADPH-Ferrihemoprotein Reductase; D014453:Glucuronosyltransferase; D005982:Glutathione Transferase