Fenofibrate affects insulin secretion in obese MSG rats. Pancreatic beta cell function was evaluated by hyperglycemic clamp. After sampling (t = 0 min) for the assay of the basal blood glucose and insulin, animals received intravenously a glucose bolus followed by a constant infusion of glucose to maintain plasma glucose level at 14 mmol/l. (A) Plasma glucose level, (B) Glucose infusion rates (GIR), (C) Plasma insulin level, and (D) Insulin stimulation ratio. Nor, normal rats. Con, water treated obese MSG rats. Fen, fenofibrate treated obese MSG rats. Values represented means ± s.e.m. (n = 6-8). *p < 0.05, **p < 0.01, ***p < 0.001 vs. control.