angiotensin (redirected from Antiotensin)

angiotensin /an·gio·ten·sin/ (-ten´sin) a decapeptide hormone (a. I) formed from the plasma glycoprotein angiotensinogen by renin secreted by the juxtaglomerular apparatus. It is in turn hydrolyzed by a peptidase in the lungs to form an octapeptide (a. II), which is a powerful vasopressor and stimulator of aldosterone secretion by the adrenal cortex. This is in turn hydrolyzed to form a heptapeptide (a. III), which has less vasopressor activity but more adrenal cortex–stimulating activity.

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an·gi·o·ten·sin (nj--tnsn)

n.

Any of a group of peptides with vasoconstrictive activity that function physiologically in controlling arterial pressure.

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angiotensin

a vasoconstrictive principle formed in the blood when renin is released from the juxtaglomerular apparatus in the kidney. The enzymatic action of renin cleaves a serum a₂-globulin, angiotensinogen, forming the decapeptide angiotensin I, which is relatively inactive. It in turn is acted upon by peptidases (converting enzymes), chiefly in the lungs, to form the octapeptide angiotensin II, a powerful vasopressor and a stimulator of aldosterone secretion by the adrenal cortex. By its vasopressor action, it raises blood pressure and diminishes fluid loss in the kidney by restricting blood flow. Angiotensin II is hydrolyzed in various tissues to form heptapeptide angiotensin III, which has less vasopressor activity but more effect on the adrenal cortex.

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angiotensin amide

an amide derivative of angiotensin II which is a powerful vasoconstrictor and vasopressor, and is used in the treatment of certain hypotensive states; usually administered by slow intravenous infusion, and sometimes intramuscularly or subcutaneously.

angiotensin-converting enzyme (ACE)

a peptidase which catalyzes the formation of angiotensin II from angiotensin I. See also ace.