Effect of SLCO1B1 polymorphism on the plasma concentrations of bile acids and bile acid synthesis marker in humans

BACKGROUND AND OBJECTIVEOrganic anion transporting polypeptide 1B1 (OATP1B1, encoded by SLCO1B1) is a sinusoidal influx transporter of human hepatocytes. Our aim was to characterize the role of OATP1B1 in the hepatic uptake of bile acids in vivo. METHODSFasting blood samples were drawn from 24 healthy volunteers with SLCO1B1 c.388AA-c.521TT (*1A/*1A) genotype, eight with c.388GG-c.521TT (*1B/*1B) genotype, 24 with c.521TC genotype, and nine with c.521CC genotype. Plasma concentrations of 15 endogenous bile acids, their synthesis marker, and cholesterol were determined by liquid chromatography–tandem mass spectrometry. RESULTSThe concentrations of ursodeoxycholic acid, glycoursodeoxycholic acid, chenodeoxycholic acid, and glycochenodeoxycholic acid were approximately 50–240% higher in individuals with the SLCO1B1 c.521CC, c.521TC, or c.388AA-c.521TT genotype than in those with the c.388GG-c.521TT genotype (P