AJP - Regulatory, Integrative and Comparative Physiology, Vol 254, Issue 2 222-R228, Copyright © 1988 by American Physiological Society
Impact of acute corticosterone administration on feeding and macronutrient self-selection patterns
B. A. Kumar and S. F. Leibowitz
Rockefeller University, New York, New York 10021.
Food intake, body weight, and meal patterns in rats are known to be
specifically influenced by circulating corticosterone (CORT). The present
study examined, in Sprague-Dawley rats, the role of CORT in the regulation
of caloric intake and choice of macronutrients during specific periods of
the light-dark cycle. Adrenalectomy (ADX) significantly attenuated the
ingestion of all three macronutrients, namely, protein, carbohydrate, and
fat, in different test periods of the light-dark cycle. This deficit was
significantly stronger just before or during the early dark hours, compared
with the light period, and it was immediately CORT reversible. During this
same early dark period, the stimulatory effect of CORT (0.5 or 2.0 mg/kg
sc) on total food intake in ADX animals was also significantly stronger
than during the light period. At this time, the CORT-injected ADX animals
consumed an even greater amount of total food intake than did the
vehicle-injected sham-operated animals and showed a significant preference
for carbohydrate, as opposed to no change or a decline in preference for
protein or fat. These findings, in light of other evidence, suggest that
CORT ensures and stabilizes the ingestion of all three macronutrients but,
in particular, stimulates carbohydrate ingestion during the important
feeding period at the dark onset when CORT levels normally peak. It is
proposed that CORT may provide a critical signal, in conjunction with
hypothalamic neurotransmitter systems, in the behavioral and metabolic
regulation of body energy balance.
