Biochemical Characterization and Cytochemical Localization of a Catecholamine-Sensitive Adenylate Cyclase in Isolated Capillary Endothelium

• Published in: Proceedings of the National Academy of Sciences - PNAS 1972-11, Vol.69 (11), p.3175-3179
• Main Authors: Wagner, Roger C., Kreiner, Peter, Barrnett, Russell J., Bitensky, Mark W.
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - metabolism; Adenylyl Cyclase Inhibitors; Adenylyl Cyclases - analysis; Adenylyl Cyclases - metabolism; Adipocytes; Adipose Tissue - blood supply; Animals; Biochemistry; Biological Sciences: Cell Biology; Capillaries; Capillaries - cytology; Capillaries - enzymology; Catecholamines - pharmacology; Cell membranes; Endothelial cells; Endothelium - enzymology; Epididymis - blood supply; Epithelial Cells; Epithelium - enzymology; Hormones; Imides - metabolism; Intercellular junctions; Male; Microscopy, Electron; Microscopy, Phase-Contrast; Phosphates - metabolism; Prostaglandins; Rats; Reaction products; Room temperature
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.69.11.3175

Capillaries were isolated from epididymal fat, and a catecholamine-sensitive adenylate cyclase found in these capillaries was characterized. The effect of various hormones on the accumulation of adenosine 3′:5′-cyclic monophosphate in capillary endothelial cells was determined and the cyclase was found to exhibit mixed alpha and beta characteristics. Cyclase was cytochemically localized in these endothelial cells with 5′-adenylyl-imidodiphosphate as a specific cyclase substrate and alloxan as a specific cyclase inhibitor. Lead imidodiphosphate was precipitated at or near the site of cyclase activity upon hydrolysis of 5′-adenylyl-imidodiphosphate by cyclase. This reaction product was observed primarily on the luminal surface of intact capillaries, in micropinocytic invaginations, in free vesicles within the cytoplasm, and in the intracellular junctions.