Distribution of estrogen receptors alpha and beta in the brain of male rats with same-sex preference.

Two distinct estrogen receptors (ERs) exist, ERα and ERβ. Both receptors participate in sexual differentiation of the rat brain and likely participate in the regulation of adult sexual orientation (i.e.

Androgen receptors immunoreactivity in the rat brain of males with same-sex preference.

Androgen receptors (AR) are crucial in the control of male sexual behavior and sex preference. AR are particularly concentrated in areas related with the neuroendocrine control of sex preference including the medial amygdala (MeA), the ventromedial nucleus of the hypothalamus (VMH), the bed nucleus of the stria terminalis (BNST), the medial preoptic area (MPOA), the nucleus accumbens (Acb), the suprachiasmatic (SCh) and supraoptic (SO) nuclei, but also seem to be important for the control of reproductive processes in the hippocampus (CA1-CA4 and dentate gyrus, DG). In the present study we analyzed the density of AR in these brain areas of adult male rats with sexual preference (established in a three-compartment box).

Male rats with same sex preference show high experimental anxiety and lack of anxiogenic-like effect of fluoxetine in the plus maze test.

Homosexual men show a 2-4 higher risk to suffer anxiety in comparison with heterosexuals. It is unknown if biological factors collaborate to increase such incidence. Fluoxetine produces differential brain activation in homosexuals as compared with heterosexuals, suggesting that it may produce a divergent behavioral effect dependant on sex-preference.