Periodicity of Food Intake and Lipogenesis in Rats Subjected to Two Different Feeding Plans

Abstract
The periodicity of food intake, apparently occurring in a 24-hour rhythm, was measured using rats fed ad libitum for 11 weeks. Rats ate mostly at night, and hardly at all during the day. The periodic pattern of lipogenesis in both liver and carcass tissues was essentially similar to that of food intake. The effect of two feeding plans, ad libitum and meal-fed, on the lipogenesis in rats was investigated by measuring the incorporation of the intraperitoneally injected acetate-1-14C into a) respiratory CO2, b) liver lipids, and c) carcass lipids. Regardless of the feeding conditions, lipogenesis in both liver and carcass during the food intake period was found to be appreciably higher than that measured before the intake period. The rate of lipogenesis in carcass tissue of rats subjected to the meal-fed plans was greater than that in rats fed ad libitum. The pattern of liver cholesterogenesis in rats fed under the two different feeding conditions was found to be analogous to that of liver lipogenesis.