title: Effects of troleandomycin administration on cholesterol 7 alpha-hydroxylase activity and bile secretion in rats.
abstract: Repeated administration of troleandomycin increased bile flow but decreased the biliary secretion of bile acids in rats. The increased bile flow was associated with a parallel increase in the biliary clearance of [14C]erythritol. Analysis of the relationship between bile flow and bile acid secretion indicated that, for any given rate of bile acid secretin, bile flow was higher in troleandomycin-treated rats than in control rats. The increased bile flow was associated with an increased activity of Na+,K+-adenosine triphosphatase in liver plasma membranes. The decreased bile acid secretion into bile was associated with a similar decrease in the bile acid pool size, a decreased bile acid synthesis rate and a decreased activity of microsomal cholesterol 7 alpha-hydroxylase. The concentration of bile acids in serum, the hepatic extraction ratio of [3H]taurocholate and its biliary transport maximum were not modified. It is concluded that repeated administration of troleandomycin increases the canalicular bile acid-independent flow but decreases the activity of cholesterol 7 alpha-hydroxylase, the synthesis, the pool size and the biliary secretion rate of bile acid in rats.
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism*; D004896:Erythritol; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000378:metabolism*; D013395:Sucrose; D013656:Taurocholic Acid / Q000378:metabolism; D014217:Troleandomycin / Q000494:pharmacology*
chemical_list: D001647:Bile Acids and Salts; D013395:Sucrose; D013656:Taurocholic Acid; D014217:Troleandomycin; D013250:Steroid Hydroxylases; D002790:Cholesterol 7-alpha-Hydroxylase; D000254:Sodium-Potassium-Exchanging ATPase; D004896:Erythritol