Ovarian influences on body weight regulation in rats with lateral hypothalamic lesions

The effect of lateral hypothalamic lesions upon the level of maintained body weight was studied in gonadally intact and ovariectomized female rats. The body weight of both the gonadally intact and ovariectomized animals declined after lesioning; but, while the weight level of the ovariectomized animals remained approximately 10% below normal, the body weight of the intact group steadily approached that of nonlesioned controls. This result suggests that ovarian factors contribute to the smaller effect on body weight as reported by others for females with lateral hypothalamic lesions. Further support for this hypothesis was found in the observations that (1) the reduced effect of lateral hypothalamic lesions on body weight of gonadally intact females was associated with prolonged periods of diestrus and (2) the normal weight suppressing effects of estrogen were attenuated by lateral hypothalamic lesions in the ovariectomized animals.