Histochemical demonstration of disulfide-groups in the lamina propria of human seminiferous tubules.

The distribution of disulfide-groups was investigated in the tunica propria of human seminifersou tubules by means of a thiosulfation/Alcian Blue + 0.8 Mol MgCl2-staining reaction. Controls had shown the absence of significant amounts of sulfhydryl- or sulfate-groups in the lamina propria, which groups would also be demonstrated by the method employed. The lamina propria of human seminiferous tubules is rich in disulfide groups. The staining reaction decreases in the region of the tubulus rectus, is only faint in the connective tissue which underlies the epithelium of the rete testis, and is absent in the lamina propria of efferent ducts. It is suggested that microfibrils and type IV collagen (both rich in cystine) are the materials responsible for the histochemical reaction described. The occurrence of multiple layers of basal lamina material (type IV collagen) and bundles of microfibrils is shown in comparative electron microscopic studies.