Bile acid synthesis is autoregulated by the enzyme:

11-alpha hydroxylase Conves 11-deoxycoisol to 11-alpha coisol (the 11-alpha isomer of hydrocoisone) Bile acid synthesis is autoregulated by 7-hydroxylase, the initial enzyme in cholesterol degradation Other enzymes are involved in cholesterol biosynthesis. Ref: Harrison, E-18, P-2462.