ATTUALI VEDUTE E PROSPETTIVE CIRCA LE INTERAZIONI TRA CATECOLAMINE E STEROIDI SESSUALI NELLA REGOLAZIONE DELLA SECREZIONE GONADOTROPICA

A review is presented of the evidence in favor of a direct action of estrogen upon specifically sensitive neurons located in the preoptic area. The effect could be an increased activity of hypothalamic adrenergic neurons ending in close relationship with cells producing the peptides 'FSHRF' and 'LHRF'. The adrenergic neurotransmitters released at that level appear to be responsible for the regulation of the secretion of the gonadotrophin releasing factors. An increased release of norepinephrine should stimulate LHRF and FSHRF secretion, while an inhibition should result from a decreased adrenergic tone. The level of peripheral sex steroids, in turn, seems to produce a feedback regulation at the hypothalamic level, through a direct action on the enzymes responsible for catecholamine synthesis and/or catabolism. Finally speculations are made about the possible clinical implications of this mechanism.