title: Evoked effects of oestradiol on hepatic cholesterol 7 alpha-hydroxylase and drug oxidase in castrated rats.
abstract: 1. Oestradiol administration in castrated rats resulted in an increased activity of the cholesterol 7 alpha-hydroxylase and a decreased activity of the drug oxidase enzyme systems. 2. Aqueous solutions of oestradiol (up to 25.10(-6)M) incubated in vitro with microsomes, binds into the microsomal membrane framework reducing the activity of both enzyme systems. 3. The specific activity of cholesterol 7 alpha-hydroxylase, drops after 3 hr preincubation with oestradiol to at least 70% of its original value. 4. Actinomycin D and cycloheximide administration reduced the oestradiol-induced and control cholesterol 7 alpha-hydroxylase activity to the same level, 6 hr after the injections.
mesh_terms: D000815:Aniline Hydroxylase / Q000037:antagonists & inhibitors; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors*; D009251:NADPH-Ferrihemoprotein Reductase / Q000037:antagonists & inhibitors; D009575:Nitroanisole O-Demethylase / Q000037:antagonists & inhibitors; D010088:Oxidoreductases / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains; D013250:Steroid Hydroxylases / Q000378:metabolism*; D013737:Testis / Q000502:physiology
chemical_list: D004958:Estradiol; D006899:Mixed Function Oxygenases; D009575:Nitroanisole O-Demethylase; D010088:Oxidoreductases; D013250:Steroid Hydroxylases; D000815:Aniline Hydroxylase; D001189:Aryl Hydrocarbon Hydroxylases; C019793:biphenyl-4-hydroxylase; D002790:Cholesterol 7-alpha-Hydroxylase; D009251:NADPH-Ferrihemoprotein Reductase