Plasma gonadotropin and testosterone values in infants with cryptorchidism.

Plasma gonadotropins and testosterone levels have been studied from day 30 +/- 6 to day 120 +/- 10 in 57 term male infants born with undescended testes-bilaterally in 22 and unilaterally in 35. Clinical follow-up of these infants showed that spontaneous testicular migration occurred at 2 to 4 months in 27 of them; the 30 others remained cryptorchid at 6 months. Plasma LH and the postnatal rise in testosterone concentration were significantly lower in patients remaining cryptorchid, either unilaterally or bilaterally, than in infants with delayed spontaneous descent of one or both testes. A significant positive correlation was found betwen plasma LH and testosterone values within these two groups of subjects. Plasma FSH levels were not different in the two groups. These data suggest a primary LH deficiency in cryptorchidism, resulting in a blunted postnatal secretion of testosterone. It may be speculated that the early postnatal deficiency of the LH-Leydig cell axis in cryptorchid patients contributes to impair both testicular migration and maturation.