Heme Oxygenase and Carbon Monoxide: Regulatory Roles in Islet Hormone Release: A Biochemical, Immunohistochemical, and Confocal Microscopic Study

摘要

Carbon monoxide (CO) has been suggested as a novel messenger molecule in the brain. We now report on the cel- lular localization and hormone secretory function of a CO-producing constitutive heme oxygenase (HO-2) in Mouse islets. Islet homogenates produced large amounts Of CO which were suppressed dose-dependently by the HO Inhibitor zincprotoporphyrin-IX (Znpp-IX). We also show, For the first time, that glucose markedly stimulates the HO Activity (CO production) in intact islets. A further poten- Tiation was induced by the HO substrate hemin. Western Blot showed that islet tissue expressed HO-2, and confo- Cal microscopy revealed that HO-2 resided in insulin, Glucagon, somatostatin, and pancreatic polypeptide cells.