Angiotensin-converting enzyme 2 (ACE2) plays a central role in vascular, renal, and myocardial physiology (1-2). In contrast to its homolog ACE, ACE2 expression is restricted to heart, kidney, and testis. Recently. ACE2 has also been shown to be a functional receptor of the SARS coronavirus (3). The normal function of ACE2 is to convert the inactive vasoconstrictor angiotensin I (AngI) to Ang1-9 and the active form AngII to Ang1-7, unlike ACE, which converts AngI to AngII. While the role of these vasoactive peptides is not well understood, lack of ACE2 expression in ace2-/ace2- mice leads to severely reduced cardiac contractility, indicating its importance in regulating heart function (4).