Glycoconjugates during the annual sexual cycle in lizard epididymal ductuli efferentes: a histochemical study

The epididymal ductuli efferentes of the lizard Podarcis sicula campestris De Betta are lined with simple, columnar, nonciliated and ciliated cells. The use of lectin histochemistry has provided information about changes of sugars associated with glycoconjugates of epithelial cells and intraluminal spermatozoa which are conveyed from the longitudinal canal to the cranial region of the ductus epididymis. Epithelial cells exhibited residues of alpha-D-mannose, N-acetylglucosamine, and beta-D-galactose-(1-4)-N-acetylglucosamine as revealed with lectins Con A, WGA and RCA120, respectively, throughout the sexual cycle. An increase of RCA120 staining was observed on microvilli of nonciliated cells and in the cytoplasm of ciliated cells during the reproductive period. However, during the following refractory period, when the organ was in regression, there was a decreased staining with Con A on microvilli and the absorbent surface of nonciliated cells, with WGA in nonciliated cells and the cytoplasm of ciliated cells, and with RCA120 on microvilli and the cytoplasm of both cell types. Terminal alpha-D-galactose residues were increasingly stained from autumn up to the reproductive period with BS I-B4 on microvilli, the absorbent surface and cilia, whereas they were entirely lacking during the refractory period. UEA I revealed alpha-L-fucose residues on the absorbent surface of nonciliated cells during the abortive and reproductive periods, increasing in the latter period when cilia also expressed this sugar. Terminal alpha/beta-D-N-acetylgalactosamine was evidenced with SBA on the absorbent surface of nonciliated cells during the reproductive period. The terminal beta-D-galactose-(1-3)-N-acetylgalactosamine dimer was never found with PNA, whereas O- and N-linked sialoglycoconjugates were present only during the reproductive period. The spermatozoa head exhibited N-linked glycans with high-mannose content, and beta-D-galactose-(1-4)-N-acetylglucosamine as well as O- and N-linked sialoglycoconjugates throughout the year. During the reproductive period, oligosaccharides with alpha-D-mannose residues increased, and oligosaccharides with terminal alpha-D-galactose, alpha-L-fucose and sialic acid-N-acetylgalactosamine dimer were also present. Unlike spermatozoa of seminiferous tubules, the spermatozoa head of the lizard epididymal ductuli efferentes exhibited seasonal variability in the lectin binding pattern which may be related to time-dependent changes in the glycoconjugate profiles of epithelial cells.