ACE2 and obesity due to melanocortin 4 receptor deficiency: ACE2 has been shown to play a pivotalrole in the “compensatory axis” of the RAS (ACE2/Ang-(1-7)/Mas) (5), opposing the effects of the classical axis(ACE/Ang-II/AT1 receptor), with implications for blood pressure regulation (6-9), heart failure (10-12), diabetes (13-16), and obesity (17, 18).