AJP - Endocrinology and Metabolism, Vol 240, Issue 5 499-E503, Copyright © 1981 by American Physiological Society
Effects of estradiol and progesterone on food intake, body weight, and carcass adiposity in weanling rats
S. M. Schwartz and G. N. Wade
The effects of estradiol and progesterone on food intake, body weight,
carcass adiposity, and adipose tissue lipoprotein lipase (LPL) activity
were investigated in weanling female rats. Treatment with estradiol
benzoate (EB) reduced body weight gain in ovariectomized (OVX) weanlings as
it does in adults. However, other responses to EB were attenuated or absent
in weanlings. EB treatment did not reduce food intake, carcass adiposity,
or adipose tissue LPL activity. This impaired responsiveness to EB may be
due to decreased levels of cytoplasmic estrogen receptors in liver and
adipose tissue (but not hypothalamus) in weanlings. On the other hand,
responsiveness to progesterone was adultlike in weanlings. Treatment of
OVX, EB-primed weanlings with progesterone increased food intake, body
weight gain, and carcass adiposity. This adultlike responsiveness to
progesterone was associated with adultlike levels of adipose tissue
progestin receptors. However, progesterone treatment did not increase
adipose tissue LPL activity in weanlings, indicating that changes in LPL
activity are not necessary for progesterone-induced obesity.
