Characterization of Immunoreactive Angiotensin in Canine Cerebrospinal Fluid as Des-Asp1-Angiotensin II

Abstract

1. Immunoreactive angiotensin II was measured in cerebrospinal fluid of four normal dogs. 2. The migration of this immunoreactive angiotensin II on polyacrylamide-slab gel electrophoresis was identical with the migration of the heptapeptide, Des-Asp¹-angiotensin II, in each case. 3. The biological activity of the material from canine cerebrospinal fluid in a pressor bioassay was similar to that of Des-Asp¹-angiotensin II. 4. The pressor activity of the canine material was abolished by treating the pressor bioassay rat with a competitive antagonistic analogue, Sar¹-Ala⁸-angiotensin II. 5. The results suggest that the biologically active immunoreactive angiotensin II present in normal canine cerebrospinal fluid is composed mainly of the heptapeptide fragment of angiotensin II, Des-Asp¹-angiotensin II.