title: Properties of renin substrate in rabbit plasma with a note on its assay.
abstract: 1. Rabbit plasma enzymes that degrade angiotensin I are inhibited completely by the combination of 2,3-dimercaptopropan-1-ol (10mm), EDTA (10mm) and chlorhexidine gluconate (0.005%, w/v). These compounds do not modify the reaction of renin with renin substrate and are termed the selective inhibitors. 2. The renin substrate concentration of plasma can be measured as angiotensin I content by incubating plasma plus the selective inhibitors with renin for a time sufficient to allow complete utilization of renin substrate. 3. This reaction obeys first-order kinetics to substrate concentrations of at least 1000ng. of angiotensin I content/ml. In general, the renin substrate concentrations of normal rabbit plasmas are less than 1000ng. of angiotensin I content/ml. Thus the time required for the complete release of angiotensin I from normal plasma is inversely related to renin activity and is independent of renin substrate concentration. 4. A method for the assay of renin substrate, taking these reaction kinetics into account, is presented.
mesh_terms: D000438:Alcohols; D000804:Angiotensin II / Q000032:analysis*; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D003377:Countercurrent Distribution; D004492:Edetic Acid; D005942:Gluconates; D006493:Heparin; D007668:Kidney / Q000502:physiology; D007700:Kinetics; D008628:Mercury; D008722:Methods; D009392:Nephrectomy; D011817:Rabbits; D012083:Renin / Q000097:blood*; D000092502:Renin Inhibitors
chemical_list: D000438:Alcohols; D000804:Angiotensin II; D004492:Edetic Acid; D005942:Gluconates; D006493:Heparin; D008628:Mercury; D012083:Renin; D000092502:Renin Inhibitors