An octapeptide that is a potent but labile vasoconstrictor. It is produced from Angiotensin I after the removal of two Amino Acids at the C-terminal by Angiotensin Converting Enzyme. The amino acid in position 5 varies in different species. To block Vasoconstriction and Hypertension effect of Angiotensin II, Patients are often treated with ACE Inhibitors or with Angiotensin II Type 1 Receptor Blockers.