Ultrastructural studies demonstrate that epithelial polarity is established in cultured mouse pre-Sertoli cells by extracellular matrix components

The effect of three different substrates, laminin, fibronectin and reconsti tuted basement membrane, on isolated mouse pre-Sertoli cells maintained in vitro has been investigated. Cultures were monitored on a daily basis by ph ase contrast microscopy, and processed for light and electron microscopy at the end of the culture period. Extra-cellular matrix components have been found to influence Sertoli cell differentiation: both fibronectin and lamin in promoted cell adhesion and differentiation, though laminin cultures show ed poor viability. Pre-Sertoli cells cultured on reconstituted basement mem brane showed the highest degree of differentiation, developing a polarized epithelial phenotype and forming cord-like aggregates; such cultures provid e a model system for the investigation of factors involved with gonadal dif ferentiation.