Relationship between insulin response to intravenous glucose and plasma lipoproteins in healthy men

In order to evaluate the influence of serum insulin levels on serum lipoprotein composition, 62 randomly selected healthy males were studied. All of them had a normal glucose tolerance. The Insulin Response to a bolus of intravenous glucose (0.50 g/kg) was significantly correlated with VLDL-Triglyceride (p less than 0.01), VLDL-Cholesterol (p less than 0.01) and with the "Atherogenic Index" (Formula: see text) (p less than 0.01). Moreover, stratifing the all population in quartiles according to the Insulin Response distribution, the highest quartile had a significant increase in Total and VLDL-Cholesterol levels (p less than 0.02), as well as in Total (p less than 0.02), VLDL (p less than 0.02) and LDL (p less than 0.01) Triglyceride, in comparison with the lowest quartile. The Atherogenic Index was also significantly elevated in the high Insulin Response group (p less than 0.005). The influence of serum insulin on lipoprotein metabolism was also evaluated by a stepwise multiple regression analysis. Body weight, Insulin Response and Exogenous Triglyceride removal were independently correlated with VLDL-Triglyceride concentration (r = 0.58, p less than 0.001). VLDL cholesterol concentration and fasting serum insulin levels were inversely correlated with HDL-Cholesterol (r = 0.49, p less than 0.001). In conclusion, in absence of any metabolic derangement, high insulin levels are associated with multiple lipoprotein abnormalities. Insulin might act as a risk factor for arterial disease through its influence on serum lipoproteins.