[Function of endogenous opioid peptides and sex steroids at the level of the central nervous system].

Gonadal steroids and beta-endorphin (beta-EP) (and probably other - EOP endogenous opioid peptides) play a role of the pivotal hormones involved in integration of several neurophysiological mechanisms. The reproductive system could be disturbed at hypothalamic level by interference of beta-EP and GnRH secretion and/or at pituitary level with response of gonadotropes to GnRH. Gonadal steroids, through a feedback mechanism, may exert similar effect on hypothalamus and/or pituitary. The action of EOP on the hypothalamo-pituitary-gonadal axis may be influenced by physiological and pathological changes in gonadal steroids during puberty, menstrual cycle in females, menopause, in case of idiopathic delayed puberty, in patients with gonadal dysgenesis or after castration. EOP seems to be "gonadostat" system that have a key role in the transmission of gonadal feedback signals to the brain.