[Interrelations between monoamines and luliberin in the synaptosomes of the medio-basal hypothalamus and its separate...

A study was made of the mechanism of interrelationship of neuromediators (biogenic amines) and LH-RH at the level of separate hypothalamic regions involved in the regulation of gonadotropic function of the hypophysis as well as at the synaptosomal level of the mediobasal hypothalamus (MBH). The steroid-dependent nature of LH-RH response in the investigated structures to monoamine administration has been shown. Noradrenaline and dopamine lowered the LH-RH level in intact animals in the area of arcuate nuclei and MBH synaptosomes, the LH level in the blood increased under the influence of noradrenaline only. Castration caused an increase in the LH-RH content in the arcuate area and its decrease in MBH synaptosomes; under such experimental conditions the LH level in the blood did not change. Serotonin in intact animals lowered the LH-RH level in the area of arcuate nuclei and MBH synaptosomes whereas in castrated animals the LH-RH level in the area of arcuate nuclei increased and decreased in synaptosomes.