GPR40/FFA1 is highly expressed in pancreatic β cells and mediates free fatty acid-induced insulin secretion. This study examined the pharmacological effects and potential for avoidance of lipotoxicity of TAK-875, a novel, orally available, selective GPR40 agonist. Insulinoma cell lines and primary rat islets were used to assess the effects of TAK-875 in vitro. The in vivo effects of TAK-875 on postprandial hyperglycemia, fasting hyperglycemia and normoglycemia were examined in type 2 diabetic and normal rats. In rat insulinoma INS-1 833/15 cells, TAK-875 increased intracellular inositol monophosphate and calcium concentration, consistent with activation of the Gqα signaling pathway. The insulinotropic action of TAK-875 (10 µM) in INS-1 833/15 and primary rat islets was glucose dependent. Prolonged exposure of cytokine-sensitive INS-1 832/13 to TAK-875 for 72 h at pharmacologically active concentrations did not alter glucose-stimulated insulin secretion, insulin content, or caspase 3/7 activity, while prolonged exposure to palmitic or oleic acid impaired β cell function and survival. In an oral glucose tolerance test in type 2 diabetic N-STZ-1.5 rats, TAK-875 (1-10 mg/kg, p.o.) showed a clear improvement in glucose tolerance and augmented insulin secretion. In addition, TAK-875 (10 mg/kg, p.o.) significantly augmented plasma insulin levels and reduced fasting hyperglycemia in male Zucker diabetic fatty rats, while in fasted normal Sprague Dawley rats, TAK-875 neither enhanced insulin secretion nor caused hypoglycemia even at 30 mg/kg. TAK-875 enhances glucose-dependent insulin secretion and improves both postprandial and fasting hyperglycemia with a low risk of hypoglycemia and no evidence of β cell toxicity.
- Received May 18, 2011.
- Revision received June 27, 2011.
- Accepted July 12, 2011.
- The American Society for Pharmacology and Experimental Therapeutics