Change in the basal secretion of gonadotropins and LH-RH content of the hypothalamus of male rats on local administration of catecholamines into hypothalamic nuclei.

Abstract

1. Administration of phentolamine (α-adrenoblocker) decreases the LH level in the blood of male rats. Administration against this background of mezatone (α-adrenostimulator) or apomorphine (DA stimulator) reverses the effect of phentolamine. 2. On administration into the PA or ARC, NA stimulates the release of gonadotropins from the adenohypophysis, by acting on the neurons of the hypothalamus producing LH-RH. The steroiddependent effect of NA is expressed only at the level of the rostral hypothalamus. 3. Administration of DA into the PA and ARC changes the concentration of LH-RH in the rostral and mediobasal sections of the hypothalamus, and increases the level of gonadotropins in the blood of intact males. However, the DA effect was steroid-dependent only at the level of the mediobasal hypothalamus.