A-779 (D-Ala7-Ang-(1-7)) is a potent and selective antagonist of angiotensin (1-7), an endogenous peptide that acts through activation of a non-AT1, non-AT2 receptor, Mas, and opposes the activity of angiotensin. A-779 has an IC50 of 0.3 nM for Mas with negligible affinity for either AT1R or AT2R.
This blocking angiotensin action affects cardiovascular function.