[Role of noradrenaline in luteinizing hormone secretion].

The role of noradrenaline in the central regulation of hypophysis gonadotropic function was examined. In intact female rats, administration or noradrenaline into the preoptic area of the diencephalon caused an increase in the blood concentration of luteinizing hormone (LH) in the second half of diestrus-2 and in the morning hours of proestrus. In ovariectomized and estradiol treated rats, noradrenaline also favoured an increase in the LH level in the blood and hypophysis, while in ovariectomized rats, administration of noradrenaline did not produce any appreciable changes in the LH content. It is suggested that ovulatory release of LH during proestrus is mediated by noradrenalinergic innervation of the rostral part of the hypothalamus. Also, the effect of noradrenaline on LH secretion is determined by estrogen levels in the peripheral blood.