The 24-hour secretory pattern of LH and the response to LHRH in transsexual men

Ten separate aspects of hypothalamic and pituitary function were studied in 13 male-to-female transsexuals and compared to the results of 7 heterosexual adult men. In 4 of 5 transsexuals, the 24-hour mean serum concentration of LH, the LH pulse frequency or amplitude, or the apparent half-life of disappearance of serum LH were greater than the 95% confidence limit of normal men. The maximum concentration of LH or FSH following the administration of 100 micrograms LHRH, the area under the response curve of LH or FSH following LHRH, or both were significantly greater than normal in 5 of 13 male-to-female transsexuals. The response of LH following the administration of LHRH was repeated in 3 subjects during estrogen therapy, and in one there was a paradoxical increase in the response of LH. Transsexualism may be associated with a neuroendocrine defect in the hypothalamus or pituitary that is characterized by high-frequency, high-amplitude pulsatile secretion of pituitary LH.