Gemfibrozil treatment of endogenous hypertriglyceridemia: Effect on insulin-mediated glucose disposal and plasma insulin concentrations

Gemfibrozil or placebo was administered for 3 months to 24 individuals with endogenous hypertriglyceridemia and normal glucose tolerance. Mean (+/- SEM fasting plasma triglyceride (TG) concentrations decreased(4.01 +/- 0.55 to 1.34 +/- 0.12 mmol/L; P < 0.001) and high density lipoprotein cholesterol concentrations increased (0.54 +/- 0.03 to 0.67 +/- 0.04 mmol/L; P < 0.001) in gemfibrozil-treated patients, associated with lower (P < 0.01-0.001) plasma free fatty acid and TG concentrations when measured at hourly intervals in response to breakfast (0800 h) and lunch (1200 h). However, day-long plasma glucose and insulin responses to meals in the groups were similar before and after treatment, as were the steady state plasma glucose and insulin concentrations at the end of a 180-min infusion of somatostatin, insulin, and glucose. Thus, marked decreases in both plasma TG and free fatty acid concentrations seen in association with gemfibrozil neither enhanced insulin-mediated glucose disposal nor lowered ambient plasma insulin concentrations in patients with endogenous hypertriglyceridemia.