Biological Activity
gpbar-a is an agonist of bile acid receptor gpbar1 [1].the g protein-coupled bile acid receptor 1 (gpbar1, tgr5) is a plasma membrane-bound receptor for bile acids. tgr5 is involved in gallstone formation and is expressed in the epithelium of human gallbladders [2].gpbar-a is an agonist of bile acid receptor gpbar1. in glutag cells, gpbar-a stimulated glucagon-like peptide (glp-1) release. in primary colonic cultures, gpbar-a increased glp-1 release by 4.2-fold. in upper small intestinal cultures, gpbar-a increased glp-1 release by 2.6-fold. in glutag cells, gpbar-a increased camp concentration by 57%. also, gpbar-a increased calcium in 56/149 cells and caused the mean response by 1.3-fold. in the presence of glucose, gpbar-a increased calcium in 148/149 cells and caused the mean response by 2.6-fold. in the presence of diazoxide (the katp channel opener, 340 μm) and 70 mm kcl, gpbar-a also increased glp-1 secretion. in colonic and small intestinal cultures, gpbar-a increased the glp-1 secretion by 2.4-fold and 1.5-fold. the glp-1 secretion mediated by gpbar-a was independent on katp channel closure [1].
References
[1]. parker he, wallis k, le roux cw, et al. molecular mechanisms underlying bile acid-stimulated glucagon-like peptide-1 secretion. br j pharmacol, 2012, 165(2): 414-423.
[2]. keitel v, cupisti k, ullmer c, et al. the membrane-bound bile acid receptor tgr5 is localized in the epithelium of human gallbladders. hepatology, 2009, 50(3): 861-870.
