Effect of rate of ingestion of diet on hexosemonophosphate shunt activity

Abstract

Young adult male rats either were allowed to eat ad libitum or were force-fed a high carbohydrate diet for 6–7 weeks; the latter animals were given amounts of diet that would "pair-gain" them against the former ones. At the end of the feeding period, the animals were killed and homogenates were made of hepatic and epididymal fat tissue or slices were prepared from the liver. The supernatants of the homogenates were assayed for glucose-6-phosphate (+6-phosphogluconate) dehydrogenase activity; the slices of liver were studied for their ability to oxidize either C-6- or C-1 C14-labeled glucose. The results of both types of measurements indicated that increased use was made of the hexosemonophosphate oxidative shunt by the tissues of the force-fed animals. It is concluded that the rate of ingestion of the diet plays a role in the regulation of traffic over specific enzymatic pathways, when multiple alternate pathways are available.