In cholestatic rats, effects of phenobarbital or cholic acid on hepatic microsomal cytochrome P-45) and b, were investigated. The total contents of both cytochrome P-450 and cytochrome bs were decreased after bile duct ligation and the administration of estradiol. When cholic acid or phenobarbital was administrated in cholestatic rats, the decrease of cytochrome P-450 was prevented.
The effects of cholic acid or phenobarbital cn both ring-hydroxylation and N-hydroxylation of AAF in cholestatic rat hepatic microsomal fraction were studied. N-hydroxylation of AAF in bil e duct ligated rat liver microsomes was reduced by 34,0,o´, but ring-hydroxylation was increased by 5176. In estradiol administrated rat, both ring-hydroxylation and N-hydroxylation of AAF was increased by 20 to 25%. In cholic acid administration, both ring-hydroxylation and. N-hydroxylation was increased by about 1076. -N-hydroxylation of AAF in phenobarbital treated rats was reduced more than ring-hydroxylation. When cholic acid was administrated simultaneously with bile duct ligation, N-hydroxylation was reduced` compared to the bile duct ligated group. Estradiol treated group which administrated with cholic acid or phenobarbital exhibited inhibitory effects of h-hydroxylation.
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