Role of Mitochondrial Cholesterol Transport in Bile Acid Biosynthesis

摘要

The faiotransformation of cholesterol to primary bile acids occurs via two main pathways (Fig. 1). In the 'neutral' or 'classic' pathway, metabolism of the sterol nucleus occurs before side-chain modifications, beginning with hydroxylation of cholesterol at the 7a position1. This reaction is catalysed by cholesterol 7a-hydroxylase (CYP7A1), the initial and rate-determining step of this pathway. In the 'alternative' pathway of bile acid biosynthesis, commonly called the 'acidic' pathway, side-c&ain modifications precede modifications in the sterol nucleus. The initial and presumed rate-determining step of this pathway is catalysed by mitochondrial sterol 27-hydroxylase (CYP27).