Estrogen and the neural mediation of female-male mounting in the rat.

Sexually receptive females mount sexually sluggish males to entice them to copulate, and estrogen and male olfactory cues mediate this female-male mounting (FMM) in the rat. This study examined whether brain regions that concentrate steroid hormones and receive olfactory projections were important for the mediation of FMM. Fos induction was observed within the medial amygdala, medial preoptic area, and ventromedial hypothalamus of ovariectomized, hormone-primed rats that displayed FMM compared with rats that did not. Excitotoxic lesions of those regions eliminated FMM, whereas implants of crystalline estradiol benzoate to the ventromedial hypothalamus, but not the medial preoptic area or medial amygdala, restored FMM. These data indicate that the ventromedial hypothalamus is a critical area of convergence of hormonal, olfactory, and somatosensory inputs for FMM.