Direct measurements of enterohepatic circulation of bile acids in the cat. Influence of contraceptive steroids and oophorectomy.
Contraceptive steroids that increase the risk of gallstones reduce the bile acid pool size and increase the cholesterol saturation in bile. To analyze mechanisms behind these effects, bile acid enterohepatic circulation was studied with direct methods in cats treated with peroral contraceptive steroids for 3 months, cats oophorectomized 1-2 months before study, and female control animals. Both administration of contraceptive steroids and oophorectomy reduced the bile acid pool size and bile acid synthesis rate. Contraceptive steroids increased water secretion by the liver at low bile acid secretion rates, reduced bile acid accumulation in the gallbladder, and increased the recycling rate of the bile acid pool. Oophorectomy did not significantly change the relation between bile acid and water secretion by the liver. The reduced bile acid pool size in animals receiving contraceptive steroids can be explained by an increased recycling rate induced by an enhanced water secretion by the liver. The possibility of a direct effect on the hepatic synthesis of bile acids by both administration of contraceptive steroids and oophorectomy cannot be excluded.
D000818:Animals; D001647:Bile Acids and Salts / Q000493:pharmacokinetics*; D002415:Cats; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D004764:Enterohepatic Circulation / Q000187:drug effects*; D004997:Ethinyl Estradiol / Q000494:pharmacology; D005260:Female; D016912:Levonorgestrel; D009644:Norgestrel / Q000494:pharmacology; D010052:Ovariectomy
D001647:Bile Acids and Salts; D003277:Contraceptives, Oral, Combined; D009644:Norgestrel; D004997:Ethinyl Estradiol; D016912:Levonorgestrel