Immunohistochemical localization of calmodulin in the testes of patients with idiopathic male infertility

The localization of calmodulin in testes of patients with idiopathic male infertility was studied using the indirect immunoperoxidase method. Specimens were obtained by testicular biopsy from 55 patients. They were divided into 26 cases of hypospermatogenesis, 11 cases of maturation arrest (8 of primary spermatocyte arrest and 3 of spermatid arrest) and 18 cases of Sertoli cell-only syndrome. Regardless of the type of testicular pathology, the types of immuno-reactive cell and the intensities of staining were the same as those in the normal testis. That is, staining for calmodulin was first found to be positive in early pachytene primary spermatocytes. It became intense in late pachytene primary spermatocytes and round spermatids. By contrast, elongated spermatids and spermatozoa were not stained. Sertoli cells were stained slightly or not at all. A calmodulin-staining index (CaM-S index) was defined as the proportion of primary spermatocytes that were stained intensely for calmodulin relative to the total number of primary spermatocytes. The indices for the testes of men with complete spermatocyte maturation arrest were significantly lower than those for the testes of normal controls and of men with hypospermatogenesis.
Degenerating late pachytene spermatocytes observed in the testes of men with spermatocyte arrest showed low calmodulin-specific immunoreactivity. Such a decrease in numbers of normal late pachytene spermatocytes might be responsible for the low CaM-S index in cases of complete spermatocyte arrest.