Food and Water Restriction Shifts Corticosterone, Temperature, Activity and Brain Amine Periodicity

TLDR

Disruption of the sleep‑wake pattern by food restriction is proposed to underlie the observed circadian changes. The study measured plasma corticosterone every 4 h over 48 h in adult male and female rats, then restricted food and water to 9:30–11:30 AM for 15 days while maintaining normal light–dark cycles. Food and water restriction produced a 12‑hour shift in the peak of plasma corticosterone and body temperature, increased daytime running activity, reversed hippocampal norepinephrine and serotonin AM/PM ratios, and demonstrated that normal light–dark cycles alone cannot sustain normal corticosterone circadian periodicity. Published in Endocrinology 95:1195 (1974).

Abstract

The circadian periodicity of plasma corticosteroid levels was determined in individual adult male and female rats, sampled every 4 hr over a 48-hr period. Access of these rats to food and water was then restricted to 9:30 AM–11:30 AM for a 15-day period, the animals being kept under normal laboratory lighting conditions (lights on 8:00 AM, off 8:00 PM). At the end of this period, such animals had a 12-hr shift in the time of the circadian peak of plasma corticosteroid levels. A similar alteration in the time of the peak of body temperature levels was also seen in these animals. Alteration of patterns of running activity, with a marked increase in daytime running activity was also present in such food and water restricted animals. There was also a reversal of AM/PM ratios of hippocampal norepinephrine and of serotonin levels in these animals. These findings demonstrate that presence of normal light-dark alteration is not sufficient for the maintenance of normal circadian periodicity of plasma corticos-teroid levels. It is suggested that disruption of the sleep-wake pattern induced by food restriction may be a factor responsible for the observed changes. (Endocrinology95: 1195, 1974)