Angiotensin II	

Angiotensin II is an octapeptide produced from the decapeptide angiotensin I by the action of angiotensin-converting enzyme.

Angiotensin II is a potent vasoconstrictor and can thus elevate blood pressure. It also directly stimulates aldosterone secretion, which leads to sodium retention and potassium loss. 

Angiotensin II binds to specific high-affinity sites in the plasma membrane of the adrenal glomerulosa cell. Unlike ACTH, cAMP does not appear to be a ‘second messenger’ in aldosterone biosynthesis. Sensitivity to angiotensin is increased by sodium deficiency, with the formation of more angiotensin receptors and an increase in binding affinity.