Hypotension and decreased renal perfusion reverse “pressure natriuresis” in the absence of angiotensin II and norepinephrine‐induced renal vasoconstriction, as shown with guanethidine administration in normal humans.48, 49 Angiotensin II dependence for maintaining GFR in severe heart failure is heightened by the common occurrence of excessive diuresis—the latter leading to worsened renal function with sodium depletion and dehydration. The gene discussed is AGT; the disease is heart failure.