Tubule-containing inclusions in the epithelial cells of the mouse epididymal duct

Comparison of lectin-staining pattern in testis and epididymis of gerbil, guinea pig, mouse, and nutria

The testis and epididymis of gerbil, guinea pig, nutria, and mouse were studied after staining with seven rhodamine-conjugated lectins to disclose the distribution of glycoproteins with different sugar residues. In the testis, the lectins showed a variable affinity for Leydig cells, tubular basement membrane, cytoplasm, acrosome, and plasma membrane of maturing spermatids as well as for Sertoli cell extensions. During acrosomal development, the staining pattern showed characteristic changes with different lectins indicating a gradual processing of the glycoprotein components. The staining in the Sertoli cell extensions displayed a cyclic change linked with the release of spermatozoa. A nuclear staining was prominent in zygotene and pachytene spermatocytes in the mouse, weak in the nutria, but absent in gerbil and guinea pig. The principal cells of epididymis showed a lectin-stained Golgi region as well as a similar staining in the apical surface, microvilli, and tubular contents. This staining was most prominent in the caput/corpus regions with some interspecies differences indicating the epididymal areas active in secretion. Narrow cells active in absorption of testis-derived material were lectin-positive in the initial segment of mouse, gerbil, and nutria epididymis. Large light cells with a strong affinity for some lectins were found in the proximal cauda of gerbil and guinea-pig epididymis. In the nutria, corresponding cells were arranged as islands within the low epithelium. The distal cauda of mouse, gerbil, and nutria was the site for lectin-stained light cells interspersed among the low principal cells. It is concluded that the high and low light cells may be active in the absorption and phagocytosis of residual bodies/cytoplasmic droplets and surplus epididymal secretory material, respectively. Thus, labeled lectins formed a useful tool in the analysis of glycoprotein distribution, processing, secretion, absorption, and degradation in the male reproductive tissues.