Involvement of the catecholamine mechanisms in the activation of mouse hypophyseotesticular complex induced by the female presence effect.

We have studied the role of the adrenergic and dopaminergic mechanisms in the activation of the endocrine testicular function of CBA/Lac and A/He male mice induced by the presence of a female in estrus without any tactile contact with a male. The alpha-adrenoreceptor blocker phentolamine inhibited an increase in the peripheral blood plasma testosterone level caused by the receptive female challenge. Propranolol blockade of beta-adrenoreceptors abruptly increased the stimulating effect of the receptive female presence on the blood testosterone level. The expression of the adrenoblocker action on the blood male sex hormone level depended on a male genotype. The dopamine receptor blocker pimozide produced a moderate effect on the blood testosterone but an attempt to separate its influence into the male sex hormone tonic secretion and the blood testosterone level against a background of sexual activation failed. It was concluded that the adrenergic mechanisms were involved in the activation of the hypothalamo-hypophyseotesticular complex induced by the presence of the receptive female.