A NOVEL ANGIOTENSIN-II BINDING-SITE IN MURINE TISSUES

A novel binding site for angiotensin II has been identified in certain murine tissues. This site, denoted AT,, is distinct from both the AT, and AT, sites, as well as the various atypical sites that have been d escribed. The site has a low affinity for angiotensin II (100 nM) and is not blocked by losartan, PD123177 or saralasin. The site shows stru ctural specificity for angiotensin II since both angiotensin III and a ngiotensin II (1-7) failed to inhibit the binding. Numerous standard d rugs, including various receptor blockers, enzyme inhibitors and thera peutic agents, showed no affinity for the site. In murine tissues the site is associated with active tissue generation, as found in spleen, placenta and growing tumors, but its occurrence appears to be rare out side of the mouse.