Culture patterns and sorting of rat Sertoli cell secretory proteins.

A cocultivation chamber and two types of permeable substrates have been used to study: (1) the culture patterns of rat Sertoli and peritubular cells, and Sertoli cells cocultured with spermatogenic cells or peritubular cells; and (2) the polarized secretion of Sertoli cell-specific proteins transferrin, S70 and S45-S35 heterodimeric protein. Substrates included a nylon mesh (with openings of 100 micron) coated with extracellular matrix (ECM) material and an uncoated microporous filter (with pores of 0.45 micron). Sertoli cells cultured on ECM-coated nylon mesh organized a continuous sheet of multilayered epithelial cells essentially devoid of spermatogenic cells while peritubular cells formed a layer of squamous cells. Sertoli cells cultured on uncoated microporous substrate formed a continuous sheet of cuboidal epithelial cells with numerous basal cytoplasmic processes projecting into the substrate and abundant apically located spermatogenic cells, while peritubular cells organized one or two layers of loose squamous cells. [35S]methionine-labelled secretory proteins resolved by two-dimensional polyacrylamide gel electrophoresis and autoradiography displayed cell-specific patterns that were slightly influenced by the type of substrate. Sertoli cells cocultured with peritubular cells on uncoated microporous substrate under conditions that enabled separation of apical and basal surfaces, secreted proteins in a polarized fashion. While transferrin was released bidirectionally, S45-S35 heterodimeric protein was released apically. S70 was detected in both apical and basal compartments. We conclude from these studies that: (1) the number of spermatogenic cells decreases when Sertoli-spermatogenic cell cocultures are prepared on ECM-coated nylon substrate; and (2) Sertoli cells in coculture with spermatogenic or peritubular cells on uncoated microporous substrate, organize continuous sheets displaying polarized protein secretion.