angiotensin
n. one of a family of peptides, including angiotensins I, II, and III, that are produced by the enzymatic action of renin on a precursor protein (angiotensinogen) in the bloodstream. Their effects include narrowing of blood vessels (vasoconstriction), increased blood pressure, thirst, and stimulation of aldosterone release from the adrenal glands. See also renin–angiotensin system.