Biochemical Characterization and Cytochemical Localization of a Catecholamine-Sensitive Adenylate Cyclase in Isolated Capillary Endothelium
Abstract
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.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- November 1972
- DOI:
- Bibcode:
- 1972PNAS...69.3175W