A Correlation of Serum Inhibin with Sperm Count and Sperm Motility in Fertile and Infertile Males

Inhibin is produced by Sertoli cells of the testis, provides negative feedback on FSH secretion, and may prove to be an important marker for the functioning of seminiferous tubules. The purpose of this study was to examine the relationship between the spermatogenic function of the tests of subfertile men and the plasma concentrations of inhibin. The study was carried out on twenty infertile (or subfertile) males and ten age-matched control subjects with proven fertility. Infertile subjects were subdivided into oligospermic, normospermic and azoospermic on the basis of their sperm count. In infertile subjects mean serum inhibin concentration (30.4 ± 22.2 pg/ml) was higher as compared to fertile subjects (25.2 ± 8.5 pg/ml), although the difference was not statistically significant (p > 0.05). Among the subgroups of infertile subjects mean serum inhibin level in azoospermics, who showed testicular atrophy on biopsy, was 8.2 ± 1.1 pg/ml, which was significantly lower (p < 0.002) than fertile subject. The mean sperm count of infertile subjects way significantly lower than fertile subjects (p < 0.01). The mean percentage of progressively active sperm was significantly lower in infertile than fertile subject (p > 0.001) while mean percentage of immotile sperms was significantly higher in infertile than fertile subjects (p < 0.001). Sluggishly motile sperms did not show a significant difference between two groups. No significant correlation of serum inhibin with either sperm count or sperm motility was observed in both, fertile as well as infertile subjects. These results indicate that serum inhibin concentration is decreased in case of damage to the seminiferous tubules, however absence of any correlation of serum inhibin with sperm count and sperm motility questions its validity in place of traditional parameters used for assessment of male infertility.