Plasma Amylin Immunoreactivity and Insulin Resistance in Insulin Resistant Relatives of Patients with Non-Insulin-Dependent Diabetes Mellitus

To explore the potential relationship between concentrations of circulating amylin and the insulin resistance observed in first-degree relatives of patients with non-insulin-dependent-diabetes mellitus (NIDDM), we studied 40 relatives compared to 35 matched controls. Two newly developed immunoassays that measure either non-glycosylated or total amylin were applied. All subjects were examined by an oral glucose tolerance test (OGTT) and by a hyperinsulinemic euglycemic clamp (insulin infusion: 0.6 mU/kg/min). Glucose tolerance was normal in all, but insulin-stimulated glucose uptake (Rd) was diminished in the relatives (p < 0.001). Area under the curves (AUCs) during OGTT for plasma glucose (p < 0.01) and serum insulin (p = 0.08), but not for plasma total and non-glycosylated amylin, were higher in relatives versus controls. In both groups, inverse correlations were found between Rd and AUC for plasma total and non-glycosylated amylin (p [all] < 0.05). However, in multiple linear regression analyses, plasma total and non-glycosylated amylin failed to influence Rd independent of serum insulin and family history of NIDDM. In conclusion, this study demonstrated inverse correlations between Rd and circulating concentrations of plasma total and non-glycosylated amylin in relatives and matched controls. These data, however, do not support the hypothesis that physiological amylin concentration are a major importance for the insulin resistance in relatives of NIDDM patients.

Key words

Amylin - Immunoassays - Insulin - Insulin Resistance - Non-Insulin - Dependent Diabetes Mellitus - Prediabetic State