Relationships Between Plasma Lipoprotein Concentrations and Insulin Action in an Obese Hyperinsulinemic Population

Relationships have been observed between lipoprotein concentrations and insulin action. These relationships may be important in explaining the association of insulin resistance and abnormalities of lipoprotein metabolism found in obesity, diabetes, and hypertriglyceridemia. We have measured plasma lipoprotein concentrations and indices of insulin action in 85 men and 56 women, all of whom were normolipidemic and had normal glucose tolerance. The subjects were obese Southwestern American Indians (body mass index 34 ± 1). Insulin action was measured via the hyperinsulinemic clamp with simultaneous indirect calorimetry. Triglyceride concentrations were inversely related to rates of total insulin-mediated glucose disposal (in men and women, respectively, r = –.37, P < .01; r = –.24, P < .10), glucose storage (r = –.31, P < .01; r = –.25, P < .10), increase in glucose oxidation (r = –.29, P < .01; r = –.24, P < .10), and, in men only, suppression of endogenous glucose production (r = –.32, P < .01). High-density lipoprotein (HDL) cholesterol concentration was positively related to rates of total insulin-mediated glucose disposal (r –.35, P < .01; r = .33, P < .05), increase in carbohydrate oxidation (r = .40, P < .001; r = .39, P < .001), suppression of endogenous glucose production (r = .24, P < .05; r = .29, P < .05), and, in men only, glucose storage (r = .35, P < .001). The relationships between lipoprotein concentrations and insulin action were independent of adiposity and insulin concentrations (with the exception of HDL cholesterol in women), and the relationships of Triglyceride and HDL cholesterol with insulin action were independent of each other. These relationships indicate that there may be a link between the development of insulin resistance and the abnormalities in lipoprotein metabolism associated with obesity, non-insulin-dependent diabetes mellitus, and hypertriglyceridemia.