Effect of Intraduodenal Perfusion of Bile Acids on the Secretion of Gastrointestinal Satiation Peptides in Healthy Male Volunteers

TGR5 is expressed in GLP-1-secreting cell lines and L cells from mice; gain- and loss-of-function models suggest a physiological role for TGR5 activation on GLP-1 secretion in rodents. TGR5 signaling showed improved postprandial glucose tolerance in obese mice, associated with marked postprandial GLP-1 release and insulin secretion. In contrast, TGR5-/- mice exhibited reduced glucose tolerance. In animals, TGR5 activation has been shown for natural bile acids (BAs) and triterpenoid compounds of plant origin, such as oleanolic acid (OA), suggesting a role for postprandial BAs in modulating nutrient-induced GLP-1 secretion. We therefore hypothesized that intraduodenal (ID) perfusions of TGR5 agonists (BAs and OA) stimulate the secretion of GLP-1 with respective changes in the glucose metabolism of healthy humans.