Ciglitazone, a New Hypoglycemic Agent: I. Studies in ob/ob and db/db Mice, Diabetic Chinese Hamsters, and Normal and Streptozotocin-Diabetic Rats

Ciglitazone, 5-[4-(1-methylcyclohexylmethoxy) benzyl]-thiazolidine-2,4-dione, is a new hypoglycemic agent orally active in the obese-hyperglycemic animal models. In C57BL 6J-ob ob mice, treatment with 100 mg /kg ciglitazone for 2 days elicited a drastic fall in blood glucose. It also decreased plasma insulin, triglycerides, and free fatty acids and food intake without affecting the body weight. Its hypoglycemic activity was independent of its effect on food intake. Regranulation of islet β-cells and increased pancreatic insulin content were observed in ob/ob mice treated for 41–44 days with 100 mg/kg/day ciglitazone. Ciglitazone showed no effect on food intake, blood glucose, or pancreatic islet β-cells in a group of lean C57BL/6J-+ /? mice concomitantly treated at a dose of 150 mg/kg/ day. In C57BL/KsJ-db/db mice, ciglitazone decreased blood glucose and food intake. The untreated db/db mice lost weight despite hyperphagia, whereas the cig-litazone-treated db/db mice gained weight. In the spontaneously diabetic Chinese hamsters, ciglitazone showed no significant effect on food intake, body weight, blood glucose, or insulin content in either plasma or pancreas, but it lowered plasma lipids. In normal rats, ciglitazone failed to affect fasting blood glucose but improved glucose tolerance without increasing insulin secretory response to glucose. In streptozotocin-diabetic rats, it showed no effect on blood glucose or glycemie response to exogenous insulin. The hypoglycemic activity of ciglitazone was specific for obese-hyperglycemic and insulin-resistant animals.