Actions of the novel oral antidiabetic agent HQL-975 in genetically obese diabetic db/db mice

The hypoglycemic effect of the novel oral agent 3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-phenyl}-2S-propylamino-propionic acid (HQL-975) was examined in db/db mice with genetically obese non-insulin dependent diabetes mellitus (NIDDM). The oral administration of HQL-975 at 3.5 and 35.3 mg/kg/d for 7 d decreased the plasma glucose level of these mice in a dose-dependent manner. HQL-975 also significantly decreased the plasma triglyceride, total cholesterol, non-esterified fatty acid and insulin levels. In the oral glucose tolerance test, HQL-975-treated mice showed improved glucose tolerance and decreased endogenous insulin secretion. HQL-975 increased glycemic response to exogenous insulin in the mice. In the HQL-975-treated db/db mice adipocytes, the glucose uptake, insulin binding, and GLUT4 expression were increased compared with those in untreated db/db mice adipocytes. These results indicate that HQL-975 improved insulin action in db/db mice through receptor and post-receptor effects. In conclusion, HQL-975 is a new oral antidiabetic agent with a hypoglycemic effect which is associated with an insulin-sensitizing effect. This agent may therefore be effective for the treatment of NIDDM.