Nateglinide-d is intended for use as an internal standard for the quantification of nateglinide by GC- or LC-MS. Nateglinide is a hypoglycemic agent. It induces insulin and somatostatin release from perfused rat pancreas when used at concentrations ranging from 0.03 to 3 μM. Nateglinide (3 µM) increases intracellular calcium levels in isolated rat pancreatic β cells, an effect that can be inhibited by the L-type calcium channel blocker nitrendipine . Nateglinide-induced secretion of insulin and somatostatin and calcium influx is also reversed by the potassium channel activator diazoxide . Oral administration of nateglinide (1.6 mg/kg) reduces blood glucose levels by 20% in fasted mice. It also decreases blood glucose levels in an oral glucose tolerance test in normal rats, genetically diabetic KK mice, and a rat model of diabetes induced by streptozotocin (STZ; ). Formulations containing nateglinide have been used in the treatment of type 2 diabetes.