preincubation of intact liver microsomes from phenobarbital-treated rats with 21-chloropregnenolone , 21,21-dichloropregnenolone , or 21,21-dichloroprogesterone in the presence of nadph caused a time-dependent decrease in progesterone 21-hydroxylase and in progesterone or androstenedione 6 beta-hydroxylase activity but had negligible or only minor effects on five other steroid hydroxylases .
C0038304
progesterone 21-hydroxylase
C0038311
steroid hydroxylases