Lectin histochemistry of the canine anal glands

The distribution and selectivity of complex carbohydrates in the canine anal glands were studied by means of lectin histochemistry, using PO-labeled lectins. The secretory epithelium of the anal glands and the excretory duct system exhibited large amounts of mainly neutral glycoproteins with various terminal sugars (alpha-D-mannose, beta-N-acetyl-D-glucosamine, alpha-N-acetyl-D-galactosamine, alpha-D-galactose, alpha-L-fucose, N-acetyl-neuraminic acid). Distinctly prominent in the secretion were alpha-L-fucose residues. This relatively hydrophobic sugar may in particular modify or control the viscoelastic properties of the anal gland mucus, so that a stable mucous coat of the rather dry faeces can be formed. In addition, it was obvious that the major part of the excretory duct system is also involved in secretion production, and that the essential function of the saccular dilatations of the excretory ducts is to ensure secretion maturation.