Angiotensin 1/2 (5-7)

Angiotensin 1/2 (5-7), (C17H27N5O4), a peptide with the sequence H2N-Ile-His-Pro-OH, MW=365.43. Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. Angiotensin is an oligopeptide and is a hormone and a powerful dipsogen. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver. It plays an important role in the renin-angiotensin system¹. Angiotensin I is formed by the action of renin on angiotensinogen. Renin is produced in the kidneys in response to renal sympathetic activity, decreased intrarenal blood pressure at the juxtaglomerular cells², or decreased delivery of Na+ and Cl- to the macula densa³.If less Na+ is sensed by the macula densa, renin release by juxtaglomerular cells is increased.Renin cleaves the peptide bond between the leucine (Leu) and valine (Val) residues on angiotensinogen, creating the ten-amino acid peptide (des-Asp) angiotensin I Angiotensin I appears to have no biological activity and exists solely as a precursor to angiotensin 2.

References:
1. Basso N, Terragno NA (December 2001). "History about the discovery of the renin-angiotensin system". Hypertension 38 (6): 1246–9.
2. Skurk T, Lee YM, Hauner H (May 2001). "Angiotensin II and its metabolites stimulate PAI-1 protein release from human adipocytes in primary culture". Hypertension 37 (5): 1336–40.
3. Williams GH, Dluhy RG (2008). "Chapter 336: Disorders of the Adrenal Cortex". In Loscalzo J, Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL. Harrison's principles of internal medicine. McGraw-Hill Medical.