Improved glucose metabolism following bariatric surgery is associated with increased circulating bile acid concentrations and remodeling of the gut microbiome

Figure 2 Course and regulation of reactions catalyzed by cholesterol 7α-hydroxylase - the rate limiting enzyme in bile acid biosynthesis. Bile acids (BAs) formed from 7α-hydroxycholesterol bind to farnezoid X receptor (FXR) and inhibit expression of the gene coding for 7α-hydroxylase, subsequently diminishing the rate of BA biosynthesis in liver. Oxysterols formed from cholesterol bind to liver X receptor (LXR) and stimulate expression of the gene coding for 7α-hydroxylase and the subsequent conversion of cholesterol to 7α-hydroxycholesterol and to BAs.