Multiple molecular weight forms of immunoreactive alpha-inhibin in human seminal plasma.

The purpose of these studies was to determine whether the total immunoreactive alpha-inhibin protein concentration in seminal plasma correlated with serum gonadotropin levels or semen characteristics and to identify the forms of alpha-inhibin present in seminal plasma. Thirty-eight serum samples from men being evaluated for infertility were selected for study based on their serum hormone profiles and semen parameters. Serum LH and testosterone levels were normal, but FSH levels ranged from normal to hypergonadotropic (> 20 IU/L). Most semen parameters were within normal ranges, but germ cell numbers ranged from normal to azoospermic. Thus, seminal plasma from these men provided a unique opportunity to examine the antigenic forms of alpha-inhibin in individuals in whom strong correlations between inhibin and FSH levels might be predicted because of the observed ranges of FSH levels and germ cell numbers. Seminal plasma alpha-inhibin was characterized by RIA or Western blotting, using an antiserum directed ...