The histochemistry of the avian parathyroid and ultimobranchial glands. I. Carbohydrates and proteins

Synopsis The non-enzyme histochemistry of the closely related parathyroid and ultimobranchial glands of the domestic fowl has been studied.The parathyroid cells and the ultimobranchial C cells gave only weakly positive reactions in tests for specific amino-acid residues. The rather stronger reactions found in the C cells were probably related to their content of polypeptide secretory granules. Carbohydrate and lipid stains also gave only negative or weakly positive reactions although the parathyroid cells did contain some free lipid.The lining cells of the ultimobranchial vesicles may be either actively secreting or inactive and cystic. Active cells contain large numbers of granules that are composed of large amounts of sulphated acid mucopolysaccharides, moderate amounts of mucoproteins and small amounts of neutral mucopolysaccharides and glycogen. Both the granular and colloidal secretions of these cells appeared to be identical in composition to the intracellular granules. The vesicular lining cells and their secretions showed strong but variable reactions for sulphydryl, disulphide and amino groups.The intermediate cell strands, which connect the ultimobranchial parathyroid foci with the vesicles, showed a range of reactions intermediate between those exhibited by parathyroid and vesicular cells.The results are discussed in relation to the structure and function of the various cell types.