[Endocrine profiles and gonadotropin response to Gn-RH of men with testicular cancer].
OBJECTIVE
To investigate the function of the hypothalamic-pituitary-testicular axis in testicular germ cell tumors, we evaluated gonadotropin responses to gonadotropin-releasing hormone (Gn-RH), semen quality, and serum levels of sex steroid hormones in patients with testicular cancer.


METHODS
Basal serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), and human chorionic gonadotropin-beta (hCG-beta) were measured before and after high orchiectomy in 20 patients with germ cell tumors of the testicle (9 with seminoma and 11 with nonseminomatous tumor). Semen quality and basal serum levels of testosterone, free testosterone, and estradiol were measured before orchiectomy. The Gn-RH test was performed before orchiectomy in all patients and after orchiectomy in patients without detectable gonadotropin levels in pre-operative serum samples. Gonadotropin levels were measured at 0, 30, 60, 90, and 120 minutes after intravenous injection of 100 micrograms of luteinizing hormone-releasing hormone (LH-RH).


RESULTS
Serum gonadotropin concentrations were not detectable in 6 of 8 (75%) men with hCG positive tumors or in 4 of 12 (33.3%) men with hCG negative tumors before orchiectomy. Before surgery, 10 men without detectable gonadotropin levels showed complete suppression of the LH and FSH responses to LH-RH and 10 men with detectable gonadotropin levels showed significant increases in the LH and FSH responses (p < 0.01) at 30 minutes. After surgery, the Gn-RH test was performed in 9 men without detectable gonadotropin levels prior to surgery. Seven of these 9 men exhibited significant increases in the LH and FSH responses (p < 0.01) at 30 minutes while no response to LH-RH before or after surgery was seen in 2 men with detectable serum hCG-beta. We observed a significantly lower sperm density (median 7.5 x 10(6)/ml, range 0.4 to 17.8) in men with hCG positive tumors than in men with hCG negative tumors (median 33 x 10(6)/ml, range 0 to 103) (p < 0.002). Although testosterone levels did not differ significantly in men with hCG positive tumors and men with hCG negative tumors, free testosterone levels were significantly higher in men with hCG positive tumors (median 28.4 ng/ml, range 8.5 to 39.8) compared with men with hCG negative tumors (median 18.7 ng/ml, range 4.9 to 24.1) (p < 0.002). Estradiol levels were significantly increased in men with hCG positive tumors (median 44 pg/ml, range 26 to 110) compared with men with hCG negative tumors (median 33.5 pg/ml, range 10 to 87) (p = 0.002).


CONCLUSIONS
The present findings indicate that serum hCG producing testicular cancers are associated with a complete suppression of the gonadotropin response to Gn-RH at the pituitary level, resulting in an inhibition of LH and FSH secretion, and also that serum hCG secreted by testicular cancers may suppresses spermatogenesis and may stimulate androgen and estradiol production by the testes. Since suppressed serum gonadotoropin levels are found in men with hCG non-producing testicular cancers, other factors derived from the tumor may cause downregulation of the gonadotropin response to Gn-RH.
Watanabe
Masanobu
M
Department of Urology, Showa University School of Medicine.
Fuji
Kozou
K
Suzuki
Kouta
K
Kitamura
Tomoyuki
T
Okumura
Daisuke
D
Kasahara
Toshio
T
Igarashi
Tsuyoshi
T
Masuyama
Tsuneo
T
Hiramori
Tomoki
T
Higaki
Masao
M
Yoshida
Hideki
H
D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004958:Estradiol / Q000097:blood; D018237:Germinoma / Q000503:physiopathology*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006062:Gonadotropins / Q000378:metabolism*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D012661:Semen / Q000502:physiology; D013736:Testicular Neoplasms / Q000503:physiopathology*; D013737:Testis / Q000503:physiopathology*; D013739:Testosterone / Q000097:blood
D018997:Chorionic Gonadotropin, beta Subunit, Human; D006062:Gonadotropins; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol