Histochemical analysis of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor)

Abstract

The distribution and selectivities of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor) were studied by light and electron microscopic histochemical methods, particularly lectin histochemistry. In the modified apocrine glands present, the apocrine secretion mode was combined with exocytosis, whereby the secretory epithelium and the luminal secretion of the ceruminous glands exhibited considerable amounts of complex carbohydrates with various terminal sugars (alpha-D-mannose, beta-D-galactose, alpha-L-fucose, alpha-N-acetyl-galactosamine, beta-N-acetyl-D-glucosamine, N-acetyl-neuraminic acid). Alpha-L-fucose and N-acetyl-neuraminic acid were distinctly prominent in secretory granules or within the free surface coat of the plasma membrane of the glandular cells, as well as in the luminal secretion. Several free sugars (alpha-D-mannose, alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine) were also detectable in the secretion of associated sebaceous glands. The ceruminous gland secretion may control viscoelasticity and/or bacterial degradation of the glandular secretion mixture to improve the protection of the external auditory canal against physical damage or microbial contamination.