Glycoprotein synthesis in the mucous cells of the vascularly perfused rat stomach. III. Mucous cells of the antrum and the duodenal glands.

Abstract

Labeled leucine, serine, galactose, glucosamine, fucose, and sulfate were administered to rat stomachs in a vascular perfusion system. Sections of gastric fundus and antrum, and of the duodenal glands, were studied by light-microscopic autoradiography. The rate of incorporation of radioactive label in the various mucous cell types of the antrum and of the duodenal glands was measured by counting the silver grains over each cell type and comparing this rate with that of the surface mucous cells of the fundus. The following major observations were made: The patterns of incorporation in the mucous cells on the surface and in the pits of the antrum did not differ essentially from those of the surface mucous cells of the fundus. On the contrary, the incorporation patterns of the surface mucous cells of the fundus differed considerably from those of the mucous cells of the antral glands and from the mucous cells of the duodenal glands. The mucous cells of the antral glands showed a lower incorporation rate of amino acids and of (amino) sugars, especially of galactose and glucosamine, but a higher incorporation rate of sulfate. The mucous cells of the duodenal glands showed a considerably higher rate of incorporation for serine, but a lower rate for glucosamine. No differences were seen for leucine, galactose, and sulfate. The relatively low synthetic activity of the mucous cells of antral glands correlates well with the various amounts of RER, Golgi system, and secretory granules, found in these cells, and with the histochemical staining characteristics of their mucous granules. The mucous cells of the duodenal glands are characterized by typical parallel arrays of their numerous RER cisternae and by a low number of small secretory granules.