Chronic food restriction and acute food deprivation decrease mrna
levels of opioid peptides in arcuate nucleus.
Kim, Eun-Mee, Catherine C. Welch, Martha K. Grace, Charles J.
Billington, and Allen S. Levine.
Research service and the department of medicine VA Medical Center,
Minneapolis 55417 Departments of food science & nutrition;
psychiatry; medicine; and surgery University of Minnesota, St. Paul
and Minneapolis, MN 55108 and 55455
APStracts 2:0320R, 1995.
Although opioid administration induces food intake, the relationship
between endogenous opioid synthesis and food consumption is unclear.
Two studies examined the effects of food restriction and deprivation
on opioid mRNA levels in the arcuate nucleus (ARC) of the rat. Body
weight significantly decreased following food restriction and
deprivation (P < 0.0001). In Experiment I, food restriction of
10%, 20%, 30% and 40% (g) of ad libitum intake for 14 d decreased
proDynorphin (proDYN), proEnkephalin (proENK) and proOpiomelanocortin
(POMC) mRNA levels in a linear fashion relative to changes in body
weight (r=0.398, P=0.011; r=0.455, P=0.0028; r=0.292, P=0.0642,
respectively). In Experiment II, 48 h deprivation significantly
decreased mRNA levels of proDYN and POMC by 23.7% (P < 0.05) and
45.6% (P < 0.01) respectively, while 24 h food deprivation
decreased POMC mRNA by 43.0% (P < 0.01). ProENK mRNA was not
affected by 24 or 48 h food deprivation. Restricting food intake
suppressed mRNA levels of proDYN, proENK and POMC by 29.7%, 22.3% and
44.4%, respectively, in 20% restricted rats and by 35.5%, 26.8%, and
45.6%, respectively, in 40% restricted rats (P < 0.01). It
appears that ARC mRNA levels of proDYN, proENK, and POMC are directly
related to the amount of food consumed and/or changes in body weight
in food restricted and deprived rats.
Received 16 August 1995; accepted in final form 25 October 1995.
APS Manuscript Number R511-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95