GPR119 was originally identified as an orphan β-cell receptor however subsequent studies demonstrated that GPR119 also regulates β-cell function indirectly through incretin hormone secretion. We assessed the importance of GPR119 for β-cell function in Gpr119-/- mice and in newly generated Gpr119βcell-/- mice. Gpr119-/- mice displayed normal body weight and glucose tolerance on a regular chow diet. After high fat feeding, Gpr119-/- mice exhibited reduced fat mass, decreased levels of circulating adipokines, improved insulin sensitivity and better glucose tolerance. Unexpectedly, oral and intraperitoneal glucose tolerance and the insulin response to glycemic challenge were not perturbed in Gpr119βcell-/- mice on regular chow and high fat diets. Moreover, islets from Gpr119-/- and Gpr119βcell-/- mice exhibited normal insulin responses to glucose and β-cell secretagogues. Furthermore, the selective GPR119 agonist AR231453 failed to directly enhance insulin secretion from perifused islets. In contrast, AR231453 increased plasma GLP-1 and insulin levels and improved glucose tolerance in wildtype and Gpr119βcell-/- mice. These findings demonstrate that β-cell GPR119 expression is dispensable for the physiological control of insulin secretion and the pharmacological response to GPR119 agonism, findings that may inform the lack of robust efficacy in clinical programs assessing GPR119 agonists for the therapy of type 2 diabetes.
This article contains Supplementary Data online at http://diabetes.diabetesjournals.org/lookup/suppl/doi:10.2337/db17-0017/-/DC1.
- Received January 4, 2017.
- Accepted February 28, 2017.
- © 2017 by the American Diabetes Association.