Some effects of ovarian hormones on food intake and body weight in female rats.

Ovarian steroids affect the food intake and body weight of rats. These effects are probably mediated by estradiol and progesterone, since these 2 hormones are more effective than their principal metabolites (estrone and 5alpha-pregnane-3,20-dione, respectively) in altering the food intake and body weight of ovariectomized rats. Estradiol seems to affect food intake by lowering the set point about which body weight is regulated in a dose-dependent fashion. These actions of estradiol can be attenuated or completely blocked by concurrent injections of progesterone. Estradiol-treated ovariectomized rats are far more responsive to the weight- and appetite-promoting actions of progesterone than are ovariectomized-adrenalectomized rats, suggesting that the principal action of progesterone on energy balance may be to interfere with the effects of estradiol.