非典型的性アイデンティティをもつ女性の黄体形成ホルモン分泌はプロジェステロンの正フィードバック作用に反応するか

In primates including humans, it is believed that there is no sex difference in the function of the hypothalamus associated with the induction of LH surge, because estrogen can induce a surge-like LH scretion in castrated males. We examined whether P could induce a surge-like LH secretion in estrogen-primed TG and TS women. Control women (N=4, 27-39 yr), TG women (N=3, 29-32 yr), and TS women (N=3, 23-29 yr) provided written informed consent. TG and TS women were diagnosed as gender identity disorder by medical specialists, and had not received any hormonal treatment. Except one in TS women, others had a regular menstrual cycle, based on the basal body temperature and the menstruation. Subjects were administered orally with 50 μg of ethinylestradiol (E) twice per day for 5 days from day 3. On day 7, subjects were injected s.c. with 12.5 mg of P. Blood samples were collected before and 3, 6, 9, 12, and 24 hour after the injetion. Serum concentrations of LH were assayed with a commercial LH kit. In control and TG women, P injection induced a surge-like LH secretion, but LH levels before P injection in TG women were slightly lower than in control women. In 2 of 3 TS women, P injection decreased LH levels, not inducing a surge-like secretion. One TS woman showed a surge-like LH secretion similar to those in TG women. We conclude that there is a sex difference in the central mechanism controlling the surge of LH secretion even in humans. [Jpn J Physiol 55 Suppl:S214 (2005)]