INFLUENCE OF PERIODICITY OF EATING ON ADIPOSE TISSUE METABOLISM IN THE RAT

Abstract

The effects of meal eating (a single 2-hour meal per day) on carbohydrate and lipid metabolism were studied in rats. Food consumption was greater in rats fed ad libitum (nibblers); however, the rate of gain was similar for both groups after an initial weight loss for the meal eaters. Isolated adipose tissue from meal eaters converted more glucose to CO₂, fatty acids, nonsaponifiable lipids, and glycogen than did tissue from nibbling animals. Acetate incorporation into fatty acids was also higher in adipose tissue from meal eaters. A higher level of pentose phosphate pathway activity in adipose tissue was indicated for meal-eating rats.Refeeding for up to 2 hours after a 22-hour fast resulted in increased lipogenesis in adipose tissue from meal eaters. Total oxidized pyridine nucleotide coenzyme (NAD–NADP) levels and the rate of glucose oxidation to CO₂in rat epididymal fat pads were found to decrease during the first 30 minutes of refeeding in meal eaters. Changes noted in metabolic pattern induced by refeeding were apparently not due to de novo enzyme synthesis. The significance of the adaptive changes noted is discussed.