Abstract
Male Wistar rats were made hyperinsulinemic by the subcutaneous inplantation of osmotically driven minipump which delivers approximately 6.4 U/day of porcine insulin for up to 2 weeks. Five percent sucrose solution was given as drinking water for hyperinsulinemic rats to prevent from hypoglycemia. Semisynthetic diet with or without 2% cholesterol, 0.5% cholic acid and 0.2% propylthiouracil were prepared.
Plasma HDL-cholesterol level was elevated by the combination of insulin infusion and sucrose supplementation and suppressed by the cholesterol-rich diet. However, the combination failed to raise HDL-cholesterol level in rats with cholesterol-rich diet.
Since cholesterol loading suppresses endogenous cholesterol synthesis, the failure of this combination to raise HDL-cholesterol level in cholesterol-fed rats suggests the important role of endogenous cholesterol synthesis for elevating HDL-cholesterol level in rat plasma.
