Biomedical subjects
Publications and source records attributed to P Sirigu.
Human parotid and submandibular glands were studied using histological techniques. Proteins rich in arginine, tyrosine, cystine-cysteine and tryptophan were present within secretory granules of seromucous acini and ducts of both glands. Acid phosphatase, ali-esterase, peroxidase and 3-beta-steroid-dehydrogenase were also demonstrated in the two glands.
Human ampullary epithelium contains numerous apical granules, which show a strong P.A.S. reaction, but do not stain with methods for acid mucins. No glycogen is detected. Acid phosphatase and non-specific esterase are localized in granules, scattered within the cytoplasm, while peroxidase activity is not demonstrable. The significance of these results is discussed.
A cytochemical study on the localization of the enzymes glucose-6-phosphate dehydrogenase, sorbitol dehydrogenase, and alkaline phosphatase was carried out in human ampullary glands. Although the former two enzymes showed a marked reactivity, alkaline phosphatase was absent from epithelial cells. On the basis of these results it is concluded that, as in the human seminal vesicle, in the ampullary gland fructose is probably secreted via the oxidative mechanism proposed by Hers (Le Metabolisme du Fructose. Bruxelles, Arscia, 1957).
The localization of lipids in the secretion of human parotid and submandibular glands has been here investigated. Ultrastructural observations following lipid extraction and histochemical data showed that lipid components are not present in the secretory granules. In fact, while histochemical reactions are completely negative, secretory granules from lipid-depleted glands retain all their morphological characters. These results led us to emphasize that, at least in human seromucous cells, lipids are not directly involved in the salivary secretion. This conclusion, which is supported by the biochemical data concerning the lipid content in human saliva, disagrees with the findings obtained in rat and guinea pig salivary glands. However, this discrepancy may be ascribed to the specific biochemical and ultrastructural differences found in the salivary glands of the various mammalian species.