Hepatic ornithine decarboxylase activity in the rat as influenced by retinyl acetate and ethanol or tryptophan.
Ethanol and tryptophan have been demonstrated earlier to induce a rapid stimulation of hepatic ornithine decarboxylase (ODC) activity in overnight-fasted rats. In this study the effect of the administration of retinyl acetate prior to administering ethanol or tryptophan was investigated. The levels of ODC activity in the livers of control and experimental rats were assayed in vitro by measuring the release of 14CO2 from DL-[1-14C]ornithine. Intraperitoneal administration of retinyl acetate (1 microgram/100 g body wt) 1 hr before tube feeding ethanol (0.75 g as a 50% solution/100 g body wt) or L-tryptophan (30 mg in 3 ml water/100 g body wt) and 3 hr before killing caused an enhanced stimulation of hepatic ODC activity compared to that when each agent was administered alone. In vitro [14C]leucine incorporation into protein using hepatic microsomes of tryptophan-treated rats with or without retinyl acetate was increased in comparison with that of controls while decreases were observed when using microsomes of ethanol-treated rats with or without retinyl acetate. Although retinyl acetate has been reported earlier to inhibit the stimulation of hepatic ODC activity due to a variety of agents, including some agents known as carcinogens or promoters, it did not act in this manner against the acute administration of ethanol or tryptophan.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003573:Cytochrome b Group / Q000378:metabolism; D015786:Cytochromes b5; D004224:Diterpenes; D004357:Drug Synergism; D004790:Enzyme Induction / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D009929:Organ Size / Q000187:drug effects; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D011132:Polyribosomes / Q000378:metabolism; D051381:Rats; D000084562:Retinyl Esters; D014364:Tryptophan / Q000494:pharmacology*; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000494:pharmacology
D003573:Cytochrome b Group; D004224:Diterpenes; D000084562:Retinyl Esters; D014801:Vitamin A; D000431:Ethanol; C009166:retinol acetate; D014364:Tryptophan; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D009955:Ornithine Decarboxylase