[Participation of catecholamines in the regulation of an induced wave of gonadotropins in ovariectomized rats].

The influence of various pharmacological agents (agonists or antagonists of catecholamine action) on the LH-RH content in certain discrete areas of the hypothalamus (in the preoptic area, arcuate nuclei and median eminence) and the LH and FSH levels were studied using a model of an induced wave of gonadotropins in ovariectomized rats receiving sex steroids. The administration of alpha-adrenoreceptor antagonists blocked a rise of the level of gonadotropins in the blood. The wave was restored when mesaton (alpha-adrenoreceptor stimulator) was administered in the presence of blockers. At the same time activation of the dopaminergic system with apomorphine was ineffective. Changes in LH-RH concentration at the hypothalamus level were recorded in the preoptic area and median eminence in the gonadotropin wave blockade and in wave restoration using various pharmacological drugs which may reflect changes in the rate of metabolic processes and transport of this neuropeptide. It was concluded that the role of catecholamines was not restricted only to the activation of LH-RH release from the terminals at the level of the median eminence but was also necessary at the level of LH-RH producing cells of the hypothalamus.