AGT and Hypertension: Recently, it was shown in our laboratory that SHRs represent a low-to-normal renin and low-to-normal angiotensin model of hypertension, as levels of renin, Ang II, and other components of the RAAS (including angiotensin III, angiotensin IV, and angiotensin 1–7) were found to be normal or decreased rather than elevated [37].