Gonadal response after a single-dose stimulation test with recombinant human chorionic gonadotropin (rhCG) in patients with isolated prepubertal cryptorchidism

BACKGROUND The evaluation of prepubertal gonadal Leydig cells secretion requires gonadotropin stimulation. Urinary hCG (human chorionic gonadotropin) is currently unavailable in many countries, however, recombinant hCG (rhCG) can be used. Our aim was to evaluate rhCG-stimulated testicular hormones in a group of patients with cryptorchidism. METHODS We evaluated 31 prepubertal boys (age range, 0.75-9.0 years) presenting with unilateral (n = 24) or bilateral (n = 7) cryptorchidism. Patients with other genital abnormalities, previous use of hCG or testosterone or previous surgeries were excluded. Blood samples were obtained at baseline and 7 days after a single subcutaneous dose of rhCG (Ovidrel® 250 mcg) to measure the testosterone, DHT (dihydrotestosterone), AMH (anti-Mullerian hormone), and inhibin B levels. RESULTS rhCG stimulation significantly increased testosterone levels from 10 ng/dl to 247.8 ± 135.8 ng/dl, increased DHT levels from 4.6 ± 0.8 to 32.3 ± 18.0 ng/dl, and increased the T/DHT ratio from 2.2 ± 0.4 to 8.0 ± 3.5. There was also a significant increase in inhibin B (from 105.8 ± 65.2 to 132.4 ± 56.1 pg/ml; p < 0.05) and AMH levels (from 109.4 ± 52.6 to 152.9 ± 65.2 ng/ml; p < 0.01) after the rhCG stimulation. CONCLUSIONS In this cohort, hormonal responses can be elicited after the rhCG stimulation test, suggesting that rhCG is a promising stimulation test to replace the urinary hCG test during the evaluation of gonadal Leydig cells function. The clinical applicability and adequate performance of rhCG testing must be investigated in future studies.