LECTIN HISTOCHEMISTRY IN THE HUMAN EPIDIDYMIS

A histochemical study using lectins to identify glycoconjugates presen t in the efferent ducts and ductus epididymidis of men without testicu lar or related disease was carried out. The lectins used and the oligo saccharide residues linked were: wheat germ agglutinin (WGA) for beta- N-acetylglucosamine and sialic acid, concanavalin A (ConA) for alpha-m annose, Ulex europaeus agglutinin (UEA-I) for alpha-fucose, Dolichos b iflorus agglutinin (DBA) for alpha-N-acetylgalactosamine, soy bean agg lutinin (SEA) for beta-N-acetylgalactosamine, and peanut agglutinin (P NA) for beta-galactose. The lectin-binding pattern in the human epidid ymis presents similarities and differences to those observed in other mammals which also showed differences between species. The present res ults revealed that regional differences along the human ductus epididy midis were less pronounced than those reported in other mammals. The e pithelial cells in the efferent ducts reacted positively to WGA. All a long the length of the ductus epididymidis, the principal cells and th e luminal content showed staining affinity for WGA and ConA. The epidi dymal principal cells and luminal content also reacted positively to D BA for alpha-N-acetylgalactosamine but only in the cauda epididymidis. A positive reaction to UEA-I was observed only in the luminal content of the cauda epididymidis. This finding suggests that changes in the oligosaccharide chains of secretions leading to a positive UEA-I react ion occur in the cauda epididymidis. The epididymal principal cells sh owed positive reactions to SEA and PNA over the apical microvilli but not in the cytoplasm. The reaction was observed in the caput and corpu s epididymidis but not in the cauda. Positive reactions to SEA and PNA were also detected in the epididymal fluid and in the cytoplasm of mi tochondria-rich cells (a minor population of epididymal epithelial cel ls). These cells also reacted to other lectins such as WGA, ConA and D BA, which were also detected in the principal cells.