Effects of lesions of the amygdala, preoptic area, and hypothalamus on estradiol-induced activity in the female rat.

Abstract

Lesions of the anterior hypothalamic nucleus and the medial preoptic area sharply attenuated enhancement of wheel running by estradiol benzoate in ovariectomized female rats. Lesions of the corticomedial amygdala had no effect on this behavior. The hormonal effects on activity were largely independent of any changes in body weight. The anterior hypothalamic and medial preoptic areas may be critically involved in the induction of activity by estradiol. No support for suggestions that the corticomedial amygdala inhibits those structures that mediate the estrogenic induction of activity was provided. In a 2nd experiment, food deprivation was used to stimulate activity. The reduction in the ability of estradiol to induce activity following anterior hypothalamic and medial preoptic lesions probably does not reflect a general inability to become more active.