[Role of catecholamines and serotonin in regulating cyclic and tonic secretion of gonadotropic hormones].

In female rats with normal estrous cycle, in the proestrus phase, a significant decrease of the serotonine level was revealed in the anterior and medio-basal parts of the hypothalamus which coincided with ascent of the releasing factor for gonadotropic hormones in the hypothalamus and for gonadotropins in the hypophysis. The dophamine level in the hypothalamic anterior and medio-basal parts changed in different ways attaining during oestrus its maximal values in the anterior and medio-basal parts of the hypothalamus. No regular changes were revealed in noradrenaline content in the course of estrous cycle in any hypothalamic area. For purposes of studying the mechanisms of regulation of the gonadotropins tonic secretion, the same parameters were recorded in androgensterile and ovariectomized rats. Levels of serotonine and noradrenaline revealed no regular connection with changes in the gonadotropins production, while the anterior part of hypothalamis dophamine concentration in the was in reverse proportion to the extent of gonadotropic secretion. Serotonine seemed to participate in regulation of the cyclic but not the tonic secretion of gonadotropins, while dophamine seemed to exert an inhibitory effect on regulation of tonic secretion of gonadotropins.