Effects of pioglitazone on glucose and lipid metabolism in normal and insulin resistant animals.

The antidiabetic effects of pioglitazone (5-[4-[2-(5-ethyl-2-pyridyl)ethoxy]benzyl]-2,4-thiazolidinedione, AD-4833, also known as U-72, 107E) were examined in normal, obese, and/or diabetic animals. When orally administered to genetically obese and diabetic yellow KK mice (2.4-24.5 mg/kg/d), and Zucker fatty rats (0.1-10 mg/kg/d) for 4 days, pioglitazone markedly decreased hyperglycemia, hyperlipidemia, hyperinsulinemia, and glucose intolerance characterized as insulin resistant states in these animals. Pioglitazone potentiated insulin-mediated glucose metabolism in the diaphragm and adipose tissues of yellow KK mice and enhanced the glycemic response to exogenous insulin in Zucker fatty rats. Four-day administration of pioglitazone (1 mg/kg/d) to aged and obese beagle dogs with moderate insulin resistance decreased plasma glucose and lipids in the fasting state, and postprandial rises in plasma triglyceride. Pioglitazone decreased plasma lipids but did not alter the plasma glucose level in young normal rats. Pioglitazone did not alter plasma glucose and lipid levels in streptozocin-diabetic rats. These results indicate that pioglitazone is effective on abnormal glucose and lipid metabolism associated with insulin resistance by enhancing insulin action on peripheral tissues. Therefore, pioglitazone is expected to be useful in treating obese non-insulin-dependent diabetes.