Three-dimensional reconstruction of a rat stage V Sertoli cell: II. Morphometry of Sertoli--Sertoli and Sertoli--germ-cell relationships.

Sertoli--Sertoli and Sertoli--germ-cell configurational relationships were studied using morphometric techniques and direct measurements as obtained from micrographs used to reconstruct a model of a rat stage V Sertoli cell. Regional areas of the Sertoli cell surface, which faced germ cells, other Sertoli cells, or noncellular structures, were expressed as relative surface area percentages; and the absolute surface areas for these regional areas were calculated. The surface areas of the reconstructed cell, in its unmagnified state, was found to be 12,163 micron2. Cell processes were enumerated and studied using morphometric techniques. The surface area of the reconstructed Sertoli cell facing germ cells and Sertoli cells was also determined. Five Sertoli cells showed extensive contact with the reconstructed cell at the level of the Sertoli--Sertoli junctional contact region. This contact region averaged 3.51 micron in width. The relative and absolute surface area of subsurface ectoplasmic specialization of the Sertoli cell that faced germ cells and other Sertoli cells was calculated, and the extent of penetration of step 17 spermatids into the Sertoli crypts was determined. Surface relationships of the reconstructed cell to cellular and noncellular elements were depicted on outline drawings of the Sertoli cell.