[Response of testosterone to chorionic gonadotropin stimulus in prepubertal cryptorchidism and retractile testes. Age-related changes in gonadal steroidogenesis. Authors'experience].

The aim of this analysis is to evaluate the gonadal function in children with true undescended testes and in those with retractile testes, in order to verify a possible impairment of the testicular steroidogenesis due to the permanent or transitory anomalous position of the gonad outside the scrotum. The authors carried out a prospective study on 29 prepubertal children affected by true undescended testes (monolateral in 20 cases and bilateral in 9), as well as on 25 prepubertal children with retractile testes (monolateral in 10 cases and bilateral in 15), assaying the testosterone (T) levels, basal and 72 hours after stimulus with human chorionic gonadotrophin (HCG) administered in a single dose of 100 U/kg i.m. Further-more, to verify the hypothesis of a possible progressive reduction of the Leydig cells function, particularly in the gonads bilaterally affected, the authors also evaluated the testosterone response to gonadotrophic stimulus compared to age (> 0 < 4 years). This study in agreement with data already published, confirms the normality of gonadal function both in children with mono or bilateral true undescended testes and in those with retractile testes. The lower the age of the subject the higher is the peak of testosterone after stimulus, confirming the active steroidogenesis of the gonads in infants and small children and sustaining the "non quiescence" of this organ during infancy, even in cases of true undescended testes.