Prolactin-releasing action of gonadotropin-releasing hormone in hypogonadal women.

To gain insight into the PRL-releasing effect of GnRH, serum PRL and gonadotropin responses to a 10-microgram iv bolus dose of exogenous GnRH were studied in hypergonadotropic hypogonadal women (HHW) and patients with functional hypothalamic amenorrhea (FHA). The results were compared with those obtained in normal cycling women during the early follicular phase of the cycle. GnRH induced a significant increase in PRL levels (P less than 0.001) in HHW compared to early follicular phase women, in whom no significant response occurred. In HHW, the maximal PRL percent increment was positively correlated with the ratio of the maximal percent increments of FSH and LH (r = 0.93). GnRH induced a significant increase in PRL levels in every FHA patient, but in four of them (high PRL responders), the PRL response was at least 5-fold greater than in the other six (low PRL responders). The clinical profiles, basal hormone concentrations, and LH responses to GnRH were similar in these two groups of FHA patients, but the FSH response to GnRH was greater (P less than 0.05) in the high PRL responders. The maximal percent increment of PRL was also positively correlated with the maximal percent increment of FSH (r = 0.76; P = 0.01). These data demonstrate that in these two hypogonadal models, the PRL response to exogenous GnRH corresponds to the FSH response and suggests that GnRH-stimulated PRL release may be mediated by a paracrine effect between FSH-enriched gonadotrophs and lactotrophs.

[1]  P. Seeburg,et al.  Immunocytochemical localization in rat brain of a prolactin release-inhibiting sequence of gonadotropin-releasing hormone prohormone , 1985, Nature.

[2]  P. Seeburg,et al.  A prolactin-inhibiting factor within the precursor for human gonadotropin-releasing hormone , 1985, Nature.

[3]  S. Yen,et al.  Prolactin-releasing action of LRF: a central catecholamine mediated event? , 1984, Life sciences.

[4]  W. Braund,et al.  Synchronous secretion of luteinizing hormone and prolactin in the human luteal phase: neuroendocrine mechanisms. , 1984, The Journal of clinical endocrinology and metabolism.

[5]  S. Yen,et al.  Concomitant pulsatile release of prolactin and luteinizing hormone in hypogonadal women. , 1983, The Journal of clinical endocrinology and metabolism.

[6]  C. Denef,et al.  Evidence for paracrine interaction between gonadotrophs and lactotrophs in pituitary cell aggregates. , 1983, Endocrinology.

[7]  D. Baird,et al.  PULSATILE SECRETION OF LH, FSH, PROLACTIN, OESTRADIOL AND PROGESTERONE DURING THE HUMAN MENSTRUAL CYCLE , 1982, Clinical endocrinology.

[8]  R. Casper,et al.  Induction of prolactin release by LRF and LRF-agonist. , 1980, Life sciences.

[9]  G. V. Loon,et al.  Bromocriptine-induced inhibition of plasma dopamine, noradrenaline and adrenaline responses to LH-RF , 1978, Nature.

[10]  S. Yen,et al.  Hypothalamic chronic anovulation. , 1978, American journal of obstetrics and gynecology.

[11]  C. Denef,et al.  A specific population of gonadotrophs purified from immature female rat pituitary , 1976 .

[12]  S. Yen,et al.  Circulating gonadotropins, estrogens, and androgens in polycystic ovarian disease. , 1975, American journal of obstetrics and gynecology.

[13]  S. Yen,et al.  Circulating prolactin levels during the menstrual cycle: episodic release and diurnal variation. , 1973, American journal of obstetrics and gynecology.

[14]  A. Littell,et al.  Disappearance rates of endogenous follicle-stimulating hormone in serum following surgical hypophysectomy in man. , 1970, The Journal of clinical endocrinology and metabolism.

[15]  P. Nakane CLASSIFICATIONS OF ANTERIOR PITUITARY CELL TYPES WITH IMMUNOENZYME HISTOCHEMISTRY , 1970, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[16]  B. Little,et al.  Disappearance rates of endogenous luteinizing hormone and chorionic gonadotropin in man. , 1968, The Journal of clinical endocrinology and metabolism.

[17]  S. Yen,et al.  Naloxone-induced prolactin secretion in women: evidence against a direct prolactin stimulatory effect of endogenous opioids. , 1985, The Journal of clinical endocrinology and metabolism.

[18]  W. Crowley,et al.  The physiology of gonadotropin-releasing hormone (GnRH) secretion in men and women. , 1985, Recent progress in hormone research.