Shark testis model: stage-dependent functions and the regulation of spermatogenesis

In mammals, a single Sertoli cell nurtures 3-4 successive generations of germ cells. Thus, it is not possible to study this cell type at a single spermatogenic stage. In the dogfish shark Squalus acanthias, a single cohort of Sertoli cells remains associated with a germ cell clone throughout its development. Moreover, different germ cell stages are topographically segregated within the testis and can be easily staged by transilluminationmicroscopy. Recently, we have developed methods for the isolation and culture of spermatocysts (Sertoli/germ cell units) and Sertoli cells only from pre-meiotic, meiotic, and post-meiotic stages of germ cell development. Here, we present data that illustrate the feasibility of using the Squalus testis model for characterizing stage-related biochemical changes in Sertoli cells.