Pituitary response to luteinizing hormone-releasing hormone analog at sea level and high altitudes

Two groups of subjects living at different altitudes were stimulated with synthetic luteinizing hormone-releasing hormone (LH-RH) or with an LH-RH analog. One hundred micrograms LH-RH was given subcutaneously to 19 men and 19 women, all normal, of reproductive age, and living at sea level, and to 19 men and 20 women living at a high altitude (2940 m). In neither sex, however, were the differences in peak responses for both gonadotropins significantly different between the sea level and high-altitude groups. Plasma levels of LH and follicle-stimulating hormone (FSH) were also measured after administration of [D-Leu6, des Gly-NH2(10)]-LH-RH ethylamide (25 micrograms subcutaneously) in 32 men and 37 women living at sea level and at high altitude. The analog induced a powerful and protracted stimulation of the release of LH and FSH irrespective of altitude and sex. The responses of men and women to the LH-RH analog, both for LH as well as for FSH, were significantly greater at sea level than at high altitudes.