Differential regulation of angiotensin peptides in plasma and kidney: Effects of adrenalectomy and estrogen treatment

Eight angiotensin peptides [angiotensin-(1-7), angiotensin II, angiotensin-(1-9), angiotensin I, angiotensin-(2-7), angiotensin-(2-8), angiotensin-(21-9), and angiotensin-(2-10)] were measured in plasma and kidney of adrenalectomized rats and estrogen-treated rats. In comparison with sham-operated rats, adrenalectomy increased plasma renin levels by 50-fold and reduced plasma angiotensinogen levels by 67%. Adrenalectomy increased plasma angiotensin peptide levels by 9- to 30-fold, but the increases in renal angiotensin peptide levels were much less than those seen for plasma. In comparison with vehicle-treated rats, estrogen treatment increased plasma angiotensinogen levels by 3-fold and reduced plasma renin levels by 41%. Estrogen treatment decreased plasma angiotensin peptide levels, whereas renal angiotensin peptide levels increased by as much as 2- to 3-fold. These results confirm the differential regulation of angiotensin peptide levels in plasma and kidney, and provide further support for the essential role of angiotensinogen in modulating plasma and tissue angiotensin peptide levels.