AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 5 676-R685, Copyright © 1983 by American Physiological Society
Food intake response to modulation of secretion of cholecystokinin in Zucker rats
C. L. McLaughlin, S. R. Peikin and C. A. Baile
Exogenous administration of cholecystokinin (CCK) decreases food intake and
elicits satiety behaviors. In the present experiments, feeding behaviors of
Zucker obese and lean rats were measured in response to treatments that
influence endogenous secretion of CCK from the duodenum. Secretion of CCK
was increased by administration of phenylalanine, a stimulant of CCK
release, and of trypsin inhibitor, which binds to trypsin, a
negative-feedback signal for CCK release. Both of these treatments
decreased the size of the first meal after a 6-h fast and average daily
meal size and increased meal frequency. Administration of trypsin,
proported to decrease secretion of CCK, increased average daily meal size
and decreased meal frequency. Pancrease, a pancreatic enzyme concentrate,
also hypothesized to act as a negative-feedback signal for CCK release,
elicited feeding behaviors similar to those of trypsin. Thus the effects of
these compounds on the feeding behavior of Zucker obese and lean rats may
be related to their effects on CCK secretion. The feeding behaviors of
obese rats were affected less than those of lean rats by exogenous
administration of CCK, but in these experiments were affected more than in
lean rats by modulation of endogenous release of CCK.
