A new approach to quantification of Sertoli cells that avoids problems associated with the irregular nuclear surface.

A new approach to quantification of Sertoli cells is described. The number of Sertoli cells per testis was calculated from the number of spermatids per testis, the number of spermatids per Sertoli cell apex, and the correction for the lifespan of spermatids enumerated per testis. To evaluate this method under different physiological conditions, testes from 28 adult (4-20-year) stallions obtained in the nonbreeding season (December-January) and from 28 adult stallions in the breeding season (June-July) were compared. Number of Sertoli cells per gram parenchyma was similar between seasons. However, the number of Sertoli cells per testis was significantly greater in the breeding season. In verification of this method, the number of spermatids per Sertoli cell apex was similar to that calculated as the ratio of spermatids to Sertoli cell in the same stallions. Likewise, absolute values similar to those of other approaches further verify the validity of this approach.