Cytochemical glucose-6-phosphatase activity in the cells of mouse pancreas and submandibular gland

Abstract

Ultrastructural localization of glucose-6-phosphatase activity was studied in the cells of the pancreas and submandibular gland of the mouse using a incubation medium modified from that of Wachstein & Meisel (1956). In pancreatic acinar cells, the reaction product for the enzyme activity was not found even after 90 min of incubation with three changes of the medium. However, the reaction product was localized in the endoplasmic reticulum and nuclear envelope of all other cell types composing the pancreas and submandibular gland. The reaction product appeared in moderate to abundant amounts in acinar cells and striated duct cells of the submandibular gland, and in the B cells, A and D cells of the pancreatic islet, but it was scarce in other cell types.

The granular convoluted tubule (GCT) cell of rodent submandibular glands

“…The major portion of the cell's organelles lie in the basal granule-free zone. By far the largest organelle is the abundant rough endoplasmic reticulum (RER), which most frequently has widely dilated cisternae with finely flocculent or grainy contents; glucose-6phosphatase activity has been demonstrated histochemically in association with the RER (Watanabe et al, 1983). Free ribosomes and polysomes abound in the intercisternal cytoplasm.…”

Histochemical Studies of Lysosomal Forming System in Osteoclasts with Calcitonin Treatment: Acid Phosphatase and Glucose-6-Phosphatase.

“…It is not, however, a conspicuous element in the cell, and the function of ER on bone resorption has not been known yet. Generally G6Pase has been well utilized as a marker enzyme of ER [17,25,42,46,47,50,51], and one of the main functions of the enzyme reported in previous studies is gluconeogenesis on phosphohydrolase activity [36]. It has been recognized that much ATP is utilized by ATPdriven proton pump on the lysosomal membrane to make lysosomal acidification [11,12,16,31,41,43,48].…”

Cytochemical glucose-6-phosphatase activity in human blood cells.

“…At present, G6Pase activity is shown to be in a variety of cell types of various organs, such as hepatocytes (31), pancreatic B cells (18), endometrial epithelial cells (26), jejunal epithelial cells (9), proximal convoluted tubule cells of the kidney (13), myocardial cells, endothelial cells, smooth muscle cells and adventitial fibroblasts of the coronary artery (3), tracheal epithelial cells (15), cells of the epididymis (11) and submandibular acinar cells (34). In all of these cell types as well as all types of blood cells except for orthochromatic erythroblasts and mature erythrocytes, as revealed in the present results, G6Pase activity is exclusively localized in the endoplasmic reticulum and nuclear envelope.…”

“…Glucose-6-phosphatase (G6Pase) activity is known to be exclusively localized in the endoplasmic reticulum and nuclear envelope of the cells (3,9,11,13,15,18,25,26,30,31,34). Therefore, as a marker for endoplasmic reticulum and nuclear envelope of blood cells, it appears more reasonable to use G6Pase than peroxidase and acetylcholinesterase, because the two enzymes are also present in cell organelles other than the endoplasmic reticulum and nuclear envelope.…”