The receptors AT1R/AGTR1 and AT2R/AGTR2 are the primary receptors that mediate the activities of Angiotensin peptides. They are widely expressed in the heart, vasculature, skeletal muscle, kidney, brain, pancreas, and adipose tissue. AT1R activation by Angiotensin II promotes vasoconstriction, cardiac contractility, renal sodium retention, insulin resistance, inflammation, fibrosis, and sympathetic nervous activity. AT1R can form heterodimers with AT2R or Mas, both of which generally antagonize these functions. The Renin R binds and activates proRenin, resulting in Renin’s cleavage of Angiotensinogen/Serpin A8 to Angiotensin I. Elevated soluble Renin R levels are associated with decreased renal function in preeclampsia, chronic kidney disease (CKD), diabetes, and essential hypertension.