Short-Term Effects of Insulin on the Blood Lipid Pattern Under Glucose Clamp Method in Non-Insulin-Dependent Diabetes Mellitus

Abstract

In order to assess the short-term effects of insulin on lipid metabolism, serum triglyceride and cholesterol were determined in 58 patients with NIDDM before and after 2 hour euglycemic clamp studies. The steady state of the plasma insulin level of 78.0±4.2μU/ml was produced by primed continuous infusion of human regular insulin (HI-rDNA, Lilly) at 40mU/m²/min for 120 min. 15%glucose was automatically infused to maintain the basal plasma glucose level. Serum triglyceride and cholesterol levels significantly fell to 84.7±2.2% and 91.7±1.4% of the basal level respectively during 2 hour glucose clamp studies. In the lipoprotein fraction of triglyceride (TG), VLDL (Sf60-400)-TG significantly decreased, but IDL₁ (Sf20-60)-TG and IDL₁ (Sf12-20)-TG showed no significant change. Each lipoprotein cholesterol slightly fell and in particular the decrease of LDL-cholesterol was significant in the group with good insulin sensitivity (glucose infusion rate≥6mg/kg/min).
In conclusion
(1) Insulin infusion decreased serum triglyceride and cholesterol level during 2 hour euglycemic clamp studies.
(2) Decrease in serum TG by insulin infusion was mainly due to the decrease in VLDL-TG.
(3) Significant decrease in LDL-cholesterol in the group with good insulin sensitivity during short-term insulin infusion indicates the important role of insulin on LDL catabolism.