Effects of insulin on net carbohydrate alterations in perfused rat liver

Abstract

The net loss of glycogen from isolated livers of nonfasted rats, cyclically perfused in situ, was significantly reduced by the addition of insulin to the medium. After 2 hr. of perfusion the amount of glycogen spared by insulin was enough to account for more than 70% of the combined net inhibitory effect of insulin on the accumulation of perfusate glucose and lactate. Lactate accumulation was decreased by insulin in the absence of added glucose. When glucose concentrations in the insulin experiments were raised to control levels by the infusion of glucose, an increase in perfusate lactate relative to control values was seen at 60 and 90 min. This rise in lactate with insulin treatment coincided with the maximum inhibitory effect of the hormone on the rate of net glucose release.