Angiotensin III is derived from angiotensin II through the action of aminopeptidase A and in turn is cleaved by aminopeptidase N to generate angiotensin IV. Angiotensin III appears to function in a manner similar to angiotensin II. It plays a role in vasoconstriction and the control of arterial blood pressure. Angiotensin III may be the effective angiotensin peptide in the central nervous system.