Reduced insulin suppression of glucose appearance is related to
subsequent energy intake and weight gain on a high fat diet in male
rats.
Pagliassotti, Michael J., Tracy J. Horton, Ellis C. Gayles, Thad A.
Koppenhafer, Todd D. Rosenzweig, James O. Hill .
SECTION OF PEDIATRIC NUTRITION, AND CENTER FOR HUMAN NUTRITION,
UNIVERSITY OF COLORADO HEALTH SCIENCES CENTER, DENVER, CO. 80262
APStracts 3:0407R, 1996.
To examine the relationship between insulin action and body weight
regulation in male rats the following studies were performed. Study
1: Rats (n=31) were fed a low-fat diet (LFD) for 4 wk and then
glucose kinetics were estimated under basal and hyperinsulinemic
conditions using the glucose clamp. Following clamps these same rats
were placed on a high-fat diet (HFD) for 5 wk. Study 2: Rats (n=30)
were fed a LFD for 3 wk and then a high sucrose diet for 1wk, to
produce selective hepatic insulin resistance. Clamps were then
performed, and following clamps these same rats were placed on a HFD
for 5 wk. Study 3: Rats (n=30) were fed a LFD for 1 wk and then a
high sucrose diet for 3 wk, to produce widespread insulin resistance.
Clamps were then performed, and following clamps these same rats were
placed on a HFD for 5 wk. The rate of glucose appearance (Ra) during
the hyperinsulinemic clamp was the only pre-HFD variable that
correlated (r=0.49, p<0.01 in study 1; r=0.51, p<0.001
in study 2) with weight gain on the HFD. Clamp Ra also correlated
with energy intake on the HFD in study 1 (r=0.64, p<0.001) and
study 2 (r=0.59, p<0.001). Clamp Ra and energy intake on the
HFD accounted for similar portions of the variance in body weight
gain on the HFD. Weight gain and fat pad mass were increased
(p<0.05) in study 2 compared to study 1. In study 3, pre-HFD
glucose kinetics were not correlated with energy intake or weight
gain on the HFD. Widespread insulin resistance did not significantly
reduce the rate of weight gain on the HFD. Thus, insulin action on Ra
can influence body weight gain on a high fat diet. The affects of Ra
on body weight gain appear to be mediated via effects on energy
intake. Selective hepatic insulin resistance can increase body weight
gain on a high fat diet but widespread insulin resistance does not
significantly reduce high fat diet-induced weight gain.
Received 2 April 1996; accepted in final form 30 October 1996.
APS Manuscript Number R190-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996