Autoradiographic localization of prazosin and rauwolscine binding sites in the human kidney.

In the human kidney, binding sites for the alpha 1-adrenoceptor antagonist 3H-prazosin and the alpha 2-adrenoceptor antagonist 3H-rauwolscine were localized and quantified by in vitro autoradiography. 3H-prazosin binding was found predominantly in the renal cortex. In the medulla, tubular structures were also specifically labelled. No binding sites, however, were detected in association with glomeruli or large blood vessels. 3H-rauwolscine labelled the medullary vascular bundles intensively, but no binding sites were associated with glomeruli or other cortical structures. Thus, the binding pattern for 3H-prazosin is quite similar in both human and rat renal cortex. There are, however, distinct differences between human and rat kidneys in the distribution of the alpha 2-adrenergic binding sites visualized with the antagonist 3H-rauwolscine.