Feeding Habits and Daily Rhythms in Tissue Glycogens in the Rat 1

Summary

Normal rats, eating ad libtium, exhibit synchronized daily rhythms in the glycogen contents of fat, diaphragm, liver, and kidney while cardiac glycogen demonstrates a cycle which is 12 hr out of phase with the other rhythms. Feeding animals hourly 1/24th of their daily food allotment either quenched the rhythms or markedly decreased their amplitudes. The fat, liver, and diaphragm of adrenalectomized rats fed hourly or allowed free access to food reacted as did the tissues of the normal rats. Feeding habits, combined with their effects on the rates of hormonal release, appear to play a major role in the generation of tissue glycogen cycles.