Cytological and lectin histochemical characterization of secretion production and secretion composition in the tubular glands of the canine anal sacs.
The study reports on secretion production and composition in the tubular glands of the canine anal sacs. For this purpose, light and electron microscopical (TEM, SEM) as well as several histochemical methods for the demonstration of lysosomal acidity, lipofuscin, and complex carbohydrates were used. The glandular tubules exhibited a pseudostratified epithelium with secretory cells of a different shape as related to secretion production activity, and regionally varying amounts of basal cells. Flat, cuboidal or columnar cells with or without apocrine-like protrusions were assembled in one glandular endpiece, although grouping of these cell types often occurred. Active secretory cells were columnar with many cytoplasmic vesicles and a typically merocrine and/or micro-apocrine exocytosis of vesicle contents. Additionally, many lysosomes of different sizes could be found, whereby in aged cells giant secondary lysosomes (autophagolysosomes, about 7 microm in diameter) occupied the major cell part. These giant lysosomes were shed by an apocrine-like process forming a final bottleneck stage of the upper cell part, and consisted of ceroid-type lipofuscin. The general carbohydrate histochemical and the lectin histochemical methods revealed that the secretion produced was composed of strongly concentrated neutral glycoproteins with the following saccharide residues: alpha-D-mannose, beta-D-galactose, beta-N-acetyl-D-glucosamine, alpha-L-fucose and N-acetyl-neuraminic acid (sialic acid); the luminal secretion contained only beta-D-galactose and, especially, N-acetyl-neuraminic acid. This luminal secretion showed a spatially orientated maturation beginning in terminal tubular regions and finishing near the excretory duct, independent of the different secretory cell types. The results obtained demonstrated highly active secretion production, with a regional variation in the glandular tubule, and at least three different modes of secretion by the secretory cells, whereby the shedding of giant lipofuscin granules seems to be very specific. The high amounts of sialic acids in the glycoproteins found may influence the rheological properties of the secretion by their water-binding capacities.
Meyer
W
W
Anatomical Institute, School of Veterinary Medicine, Hannover, Germany. wmeyer@anat.tiho-hannover.de
Tsukise
A
A
Neurand
K
K
Hirabayashi
Y
Y
D000695:Anal Sacs / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001826:Body Fluids / Q000737:chemistry / Q000378:metabolism; D004285:Dogs; D005088:Exocrine Glands / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D006651:Histocytochemistry; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning
D037102:Lectins