ROLE OF GALANIN IN THE REGULATION OF SOMATOTROPE AND GONADOTROPE FUNCTION IN YOUNG OVULATORY WOMEN

The aim of the study was to elucidate the role of the neuropeptide gal anin in the regulation of somatotropic and gonadotropic function in no rmal women. Thirteen normally ovulating (aged 28 to 40 years), non-obe se (body mass index, 18.4 to 27.1 kg/m(2)) women with infertility due to a tubal or male factor were studied. Each woman underwent three tes ts: (1) bolus intravenous (IV) injection of growth hormone (GH)-releas ing hormone (GHRH) (1-29)NH2 1 mu g/kg plus gonadotropin-releasing hor mone (GnRH) 100 mu g at time 0; (2) IV infusion of porcine galanin 500 mu g in 100 mt saline from -10 minutes; and (3) bolus IV injection of GHRH(1-29)NH2 1 mu g/kg plus GnRH 100 mu g at time 0 plus IV infusion of porcine galanin 500 mu g in 100 mt saline from -10 to +30 minutes. All results are expressed as the mean +/- SEM. GH peak after GHRH was 14 +/- 5 mu g/L; porcine galanin significantly increased serum GH (GH peak, 7.3 +/- 1.2) with respect to baseline levels. No significant di fferences were observed between either GH peak or GH absolute values a fter galanin as compared with GHRH alone. Porcine galanin significantl y enhanced GH response to GHRH (peak, 31.4 +/- 4.4 mu g/L) with respec t to either GHRH or galanin alone. Luteinizing hormone (LH)/follicle-s timulating hormone (FSH) peaks after GnRH were 16.5 +/- 5.3 and 17.4 /- 4 IU/L, respectively. Porcine galanin did not cause significant inc reases in serum LH and FSH levels with respect to baseline. Galanin co administration slightly increased LH (peak, 25 +/- 6.9 IU/L) but not F SH (peak, 17.1 +/- 3.2) maximal responses to GnRH. In conclusion, gala nin plays a significant role in the regulation of GH secretion in wome n, as well as in men. Moreover, this report suggests a minor role of g alanin in the regulation of the hypothalamic-pituitary-ovarian axis in women. Copyright (C) 1995 by W.B. Saunders Company