Studies of the Renin-Angiotensin in Vertebrates

• Main Author: Tree, Malcolm
• Format: Thesis
• Language: English
• Published: ProQuest Dissertations & Theses 1972
• Subjects: Anguilla anguilla
• Online Access: http://theses.gla.ac.uk/78612/; http://theses.gla.ac.uk/78612/1/11012025.pdf

The biochemistry and physiology of the renin-angiotonsin system in vertebrates is reviewed. Techniques for measuring some components of this system have been developed. The intention was to develop techniques that could be applied to studies in most if not all vertebrates. Unlike mammalian renal renin, it was not possible to bioassay renal renin of fish, amphibia, reptiles and birds simply with the rat blood pressure preparation. It was necessary to develop enzyme kinetic techniques based on the hydrolytic action of the enzyme renin on its protein substrate to form the vasopressor peptide angiotensin. Angiotensin is destroyed in all tissues and body fluids by peptidases (angiotensinases). In developing these techniques it was important to inactivate angiotonsinases and this aspect was considered at length. Many enzyme poisons were tested and often their effectiveness was pH-dependent. Diisopropyl phosphite (DP) inhibited kidney angiotensinases satisfactorily in most of the 40 vertebrate species that were studied. These vertebrates included representatives from the five major classes. DP also inactivated angiotensinase in eel (Anguilla anguilla) plasma and the eel corpuscle of Stannius. In other studies with fish and mammalian plasma, angiotensinases were also effectively inhibited by a combination of phenanthroline and ethylene diamine tetra acetate. The optimal conditions for the enzymic reaction of renin were considered and it was found that some properties of the fish renin reaction differ from those established in mammals. The eel renin reaction with eel renin---substrate was optimal at 20