Ultracytochemical detection of heteropolysaccharides in the cat submandibular gland.

We have investigated the morphology and the ultrastructural distribution of complex carbohydrates in the cat submandibular gland using the high iron diamine-thiocarbohydrazide-silver proteinate (HID-TCH-SP), the low iron diamine-thiocarbohydrazide-silver proteinate (LID-TCH-SP), and the periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) sequences. The results of morphological analyses show that, in addition to already known cellular populations, in striated ducts a further cellular type containing glycogen is present. The histochemical staining showed that demilunar cells secrete polysaccharides that have carboxylated but not sulphated glycosidic residues, whereas acinar cells elaborate secretion products rich in carboxylated and sulphate-containing complex carbohydrates. Vicinal glycol groups are present as constituents of the secretion in demilunar, acinar, and ductal cells.