Lectin-binding sites in the seminal vesicles of entire and castrated horses

This research was undertaken to determine the glycoconjugates secreted by the glandular epithelium of the seminal vesicles in the entire and castrated horses using lectin histochemistry in combination with sialidase digestion and deglycosylation pre-treatments. The following lectins were used: Con-A, UEA-I, LTA, WGA, GSA-IB4, SBA, PNA, ECA and DBA. In the entire stallion, the glandular cells expressed the following sugar residues: α-Fuc, internal GlcNAc, terminal β- and α-GalNAc, β-D-Gal-(1–4)-GlcNAc and α-Gal included in O-linked oligosaccharides; β-Gal-(1–3)-GalNAc belonged to both O- and N-oligosaccharides whereas terminal GlcNAc belonged to N-linked glycans. Additionally, α-Gal and β-Gal acted as acceptor sugars for sialic acid moieties. In castrated horses, the glandular epithelium showed a different lectin labelling pattern. In particular, we evidenced internal GlcNAc, α-GalNAc, β-Gal-(1–3)-GalNAc in both O- and N-linked glycoproteins whereas β-GalNAc and β-Gal-(1–3)-GalNAc in O-linked glycoproteins. The differences evidenced in the lectin profile between the stallion and castrated horse suggested a hormonal regulation of the glycoconjugate production. Additionally, the plurality of glycomolecules detected in the secretions of the stallion may be involved in spermatozoa maturation.