Glucokinase is located in secretory granules of pancreatic D-cells

We immunohistochemically examined the distribution of glucokinase in rat pancreatic islets. Glucokinase immunoreactivity under light microscopy was detected in the cytoplasm of somatostatin cells as well as in that of insulin cells. No specific immunoreactivity was detected in glucagon and pancreatic polypeptide cells. In somatostatin cells, glucokinase immunoreactivity was located by electron microscopy exclusively within secretory granules.