Acute fasting decreases sexual receptivity and neural estrogen receptor-alpha in female rats.

Acute food deprivation or chronic food restriction suppresses reproduction in female mammals. Although a link between undernutrition and ovarian function is well established in rats, a similar link with reproductive behavior in this species is yet to be described. Therefore, we compared the display of estrous behaviors induced by exogenous steroid hormone treatment in ovariectomized fed and fasted rats. In addition, estrogen receptor-alpha immunoreactivity (ERIR) was measured in fed and fasted animals to determine whether changes in behavior were associated with changes in the number of detectable ERIR-containing cells in several brain regions. Fasting for 74 h decreased lordosis quotients (LQ) and lordosis ratings (LR) in ovariectomized, steroid-primed rats. The number of detectable ERIR cells decreased after a 74-h fast in the mid-region of the arcuate (ARC), paraventricular (PVN) and ventromedial nuclei of the hypothalamus (VMH) and the ventral bed nucleus of the stria terminalis (BST) but did not change in a number of other areas examined. Taken together, these data demonstrate that, similar to the effect on the reproductive-endocrine axis, food deprivation for 74 h suppresses steroid-induced display of lordosis in adult, female rats. Furthermore, this suppression in sexual receptivity is associated with a decrease in ERIR in a number of areas, including the VMH, a region of the hypothalamus known to be critical for the display of reproductive behaviors in female rats.