TESTICULAR RESPONSIVENESS TO A SINGLE HCG DOSE IN PATIENTS WITH TESTICULAR FEMINIZATION

The suggestion that androgens may regulate testosterone (T) production in rat Leydig cells by a receptor-mediated feed-back mechanism, led us to investigate whether in vivo the absence of testicular androgen receptors, as it occurs in testicular feminization (TF), may modify the characteristic testicular response observed in men and prepubertal children after a single dose of hCG. Subjects consist of: 1) six normal men, 2) two adult patients with the complete form of androgen insensitivity syndrome (TF), 3) 12 normal prepubertal boys, 4) one prepubertal boy with the same form of TF. Each subject received i. m. a single dose of hCG 3500 IU/m2 b. s. and blood samples were collected basally and 2, 4, 24, 48, 72 and 96 hours after the hormonal stimulus. Serum levels of T, 17α hydroxyprogesterone (17OHP) and 17β estradiol (E2) were measured at each collection time. In normal men a significant increase in T (M ± SE) was observed at 4 h (758.6 ± 135 ng/dl, P < 0.05) and a more significant increase at 48 h (1082 ± 60.3 ng/dl, P < 0.001). E2 and 17OHP peaked significantly at 24 h (81.5 ± 9.6 pg/ml and 460.7 ± 90.9 ng/dl respectively). This response pattern is characteristic of the testicular desensitization which occurs in normal man after a single hCG dose. The same response pattern has been observed in the two TF adult patients suggesting that human testicular desensitization in vivo does not depend on androgen receptors. In normal prepubertal boys there was a slow and progressive increase in T which reached the value of 177 ± 8.7 ng/dl (P < 0.001) at 48 h and remained stable for an additional 48 hours. Plasma E2 and 17OHP did not change after hCG stimulation. The prepubertal patient with TF showed the same response. This finding further seems to exclude any possible role of androgen receptors in testicular response to hCG also in prepubertal age.