Effects of taurocholic acid on glycemic, glucagon-like peptide-1, and insulin responses to small intestinal glucose infusion in healthy humans

Abstract

Context: In vitro and animal studies suggest that bile acids have the capacity to reduce blood glucose by stimulating glucagon-like peptide-1 (GLP-1) and, thereby, insulin. Objective: This study evaluated the effects of intrajejunal taurocholic acid (TCA) on blood glucose, GLP-1, and insulin responses to jejunal glucose infusion in healthy men. Participants and Design: Ten healthy men were each studied on 2 days in a double-blind, randomized order. After the subjects fasted overnight, a jejunal catheter was positioned and a balloon inflated 30 cm beyond the pylorus with aspiration of endogenous bile. Two grams TCA in saline, or saline control, was infused beyond the balloon over 30 minutes, followed by 2 g TCA or control, together with 60 g glucose, over the next 120 minutes. Blood was sampled frequently for the measurements of blood glucose, total GLP-1, insulin, C-peptide, and glucagon. Results: Intrajejunal infusion of TCA alone (t = -30 to 0 minutes) had no effect on blood glucose, GLP-1, insulin, C-peptide, or glucagon concentrations. During intrajejunal glucose infusion (t = 0 to 120 minutes), blood glucose concentrations were lower (P< .001), and plasma GLP-1 (P