Rat Liver Glucose 6-Phosphate Dehydrogenase

Abstract

Abstract Rates of rat liver glucose 6-phosphate dehydrogenase synthesis and degradation in vivo have been measured by following the time course for the induction of the enzyme by carbohydrate diets and insulin. If rats previously adapted to a commercial pellet diet are fed a 60% carbohydrate diet, the rate of glucose-6-P dehydrogenase synthesis increases up to 80-fold, and the first order rate constant for the degradation in vivo of the enzyme is increased 4.6-fold. The rate of synthesis of glucose-6-P dehydrogenase in these rats increases in proportion to the caloric consumption of carbohydrate, whether or not that carbohydrate is able to stimulate the release of insulin from the pancreas. Although large doses of insulin are able to induce the synthesis of glucose-6-P dehydrogenase, this induction can be attributed to the ability of insulin to stimulate the appetite. It is concluded that insulin has no direct effect on the regulation of glucose-6-P dehydrogenase levels under our experimental conditions.