Effects of Long-Term Testosterone Administration on Gonadotropin Secretion in Agonadal Female to Male Transsexuals Compared with Hypogonadal and Normal Women*

We investigated the effects of long term testosterone (T) administration on pulsatile gonadotropin secretion in agonadal women and the effects of estradiol (E2) on gonadotropin secretion in eugonadal women in the follicular phase of the menstrual cycle. We studied 4 groups: A) 28 eugonadal women in the early follicular phase of the menstrual cycle, B) 11 hypogonadal women, C) 13 agonadal female to male (f-t-m) transsexuals treated for at least 3 months with 120-160 mg T undecanoate (TU)/day, orally, and D) 5 agonadal f-to-m transsexuals treated for at least 6 months with 250 mg of a mixture of testosterone esters, im (im T-esters), every 2 weeks. The eugonadal women in the early follicular phase had a mean serum E2 level of 193 ± 94 (±sd) pmol/L, significantly higher (P < 0.01) than that in the hypogonadal women (60 ± 24 pmol/L), whereas there was no difference in the mean serum T levels (1.8 ± 0.7 vs. 2.3 ± 1.5 nmol/L). The higher serum E2 level in the eugonadal women was associated with a significantly ...