AJP - Endocrinology and Metabolism, Vol 242, Issue 6 437-E444, Copyright © 1982 by American Physiological Society
Body composition and adiposity in LH-lesioned and pair-fed obese Zucker rats
K. M. Milam, R. E. Keesey and J. S. Stern
It has been reported previously that lateral hypothalamic (LH) lesions
alter body composition including reducing adipocyte cellularity in lean and
obese Zucker rats. The present experiment was designed to determine whether
these alterations in body composition and adipose cell number are secondary
to the reduced energy consumption of LH-lesioned rats or to a direct effect
of the hypothalamic lesion. Groups of lean and obese Zucker rats,
sustaining lesions of the lateral hypothalamus at 10 wk of age, maintained
body weight at 72% that of nonlesioned controls until killed at 32 wk.
Pair-feeding nonlesioned rats to the intakes of lean and obese LH-lesioned
rats produced a reduction in adipocyte number similar to that caused by
lesions. However, neither the lean nor obese LH-lesioned rats displayed an
increase in cell number when fed a palatable diet that markedly increased
carcass lipids. This finding suggests that adipocyte number may be
constrained in LH-lesioned rats. These and further observations that 1)
lean control rats maintained a higher body weight than the LH-lesioned rats
to which they were pair fed and 2) in obese rats, food restriction further
reduced protein deposition and elevated plasma insulin relative to
comparably fed LH-lesioned obese rats suggest that the LH syndrome is
mimicked by simple food restriction.
