AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 3 311-R317, Copyright © 1982 by American Physiological Society
Developmental study of adipose cellularity in lateral hypothalamic-lesioned Zucker obese rats
K. M. Milam, R. E. Keesey, L. H. Storlien and J. S. Stern
Ten-week-old lean and obese Zucker rats were sham lesioned or received
bilateral, electrolytic lesions of the lateral hypothalamus (LH). They were
maintained on a wet mash diet until killing at 15 or 32 wk of age; control
lean and obese rats were also killed at 6 and 10 wk. Body composition
analyses were performed and adipocyte cellularity of epididymal,
retroperitoneal, and subcutaneous depots were calculated. Changes in body
composition of LH-lesioned rats, though similar in the two genotypes on an
absolute basis, differed on a percentage basis due to the extreme adiposity
of the obese rats. Retarded development of protein depots in both lesioned
lean and obese rats was apparent at 15 but not 32 wk. Relative to genotypic
controls, lesioned lean and obese rats had smaller adipose depots by 32 wk
due to decreased adipocyte size in lean rats and reduced adipocyte number
in the obese. This genotype-specific response was probably due to the
chronic hyperplasia of adipocytes unique to the obese rats. This
distinctive developmental pattern of the epididymal depot is discussed.
