Spermiation, the process by which late spermatids separate from the Sertoli
cell, is disrupted by a number of toxicants. In this study, we used immuno
histochemistry (IHC) to identify some of the proteins associated with the s
permatid-Sertoli junction. We confirmed the presence of tubulin, actin, and
vinculin at the luminal edge of the seminiferous tubule, and we determined
that paxillin is also present here. In other cell types, these proteins ha
ve been reported to colocalize with beta integrins. Numerous attempts to id
entify beta integrins by IHC and by use of Western blots were unsuccessful.
Clear evidence was found for the presence of N-cadherin and its associated
intracellular proteins: beta-catenin, pp120, desmoglein, pp60(src) and Csk
. In addition, N-cadherin and desmoglein were found around spermatids retai
ned by the epithelium. From these data and previous literature reports, we
propose a hypothetical model for spermatid adhesion and the control of that
adhesion, thus providing a framework for hypotheses on the steps involved
in the complex process of spermiation in rat testes.