Subcellular distribution of hydralazine in rat single vascular muscle cells.

High specific activity (20 Ci/mmol) tritiated hydralazine (3Hyd) distribution in isolated, cultured vascular muscle cells was determined to identify the sites of Hyd binding. 3Hyd dose-dependently bound to extracellular protein and to the area of organelles which secrete these proteins. Increased extracellular binding after Hyd pre-exposure suggests new binding sites may be exacerbated as a result of Hyd interactions. These experiments suggest a potentially important feature of the mechanism of action of this directly acting vasodilator.