Medical Pharmacology Chapter 24:  Vasoactive Peptides

• Overview: Biosynthesis

  1. Renin catalyzed conversion of angiotensinogen to angiotensin I

  2. Conversion of angiotensin I to angiotensin II by converting enzyme

  3. Degradation of angiotensin II by peptidases

• Renin/Regulation of renin secretion

  • Renin:

    • Aspartyl protease (catalyzes the conversion of angiotensinogen  to angiotensin I (decapeptide)

      • Renin Protein Structure

        Swaminathan J and MSD Staff at the Europeam Bioinformatics Institute. "Cartoon representation of the molecular structure of the protein registered with 2ren code." http://en.wikipedia.org/wiki/File:PDB_2ren_EBI.jpg

    • Preprohormone is conveted to  prohormone which is converted to renin, a glycoprotein.

    • Most circulatory renin is synthesized in the kidneys

      • Nephron synthetic and storage site: juxtaglomerular apparatus

        1. Afferent and efferent arterioles contain granular cells;  juxtaglomerular cells are a synthetic, storage, and renin release site.

        2. Macula densa:  specialized tubular segment: associated with juxtaglomerular vascular elements

           1. Komorniczak M "Renal Corpuscle" http://en.wikipedia.org/wiki/File:Renal_corpuscle.svg

        3. Afferent and efferent arterioles and macula densa are innervated by the adrenergic system.

Reid, I.A., Vasoactive Peptides, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 287-303.