The L-α-amino acid receptor GPRC6A is expressed in the islets of Langerhans but is not involved in L-arginine-induced insulin release.

GPRC6A is a seven-transmembrane receptor activated by a wide range of L-α-amino acids, most potently by L-arginine and other basic amino acids. The receptor is broadly expressed, but its exact physiological role remains to be elucidated. It is well established that L-arginine stimulates insulin secretion; therefore, the receptor has been hypothesized to have a role in regulating glucose metabolism. In this study, we demonstrate that GPRC6A is expressed in islets of Langerhans, but activation of the receptor by L-arginine did not stimulate insulin secretion. We also investigated central metabolic parameters in GPRC6A knockout mice compared with wildtype littermates and found no difference in glucose metabolism or body fat percentage when mice were administered a standard chow diet. In conclusion, our data do not support a role for GPRC6A in L-arginine-induced insulin release and glucose metabolism under normal physiological conditions.