Effects of ciglitazone on endogenous plasma islet amyloid polypeptide and insulin sensitivity in obese-diabetic viable yellow mice.

The role of islet amyloid polypeptide, also known as amylin, in insulin resistance and in the etiology of diabetes has been a subject of debate. Increased plasma amylin levels have been observed in both obese and type II diabetic patients. However, data on endogenous amylin levels with relation to pharmacological interventions have not been reported. In this study, chronic treatment of obese-diabetic viable yellow mice with ciglitazone was shown to significantly alter various parameters. Blood glucose and plasma insulin, triglyceride, and amylin levels were reduced and glucose tolerance in the presence of exogenous insulin was improved. Insulin/amylin ratios which were found to be significantly elevated in diabetic mice as compared to normal controls, were decreased after ciglitazone treatment. However, observed decreases in both amylin and insulin concentrations due to ciglitazone treatment and their subsequent increases upon withdrawal of treatment were correlated, suggesting cosecretion.