title: Angiotensin II-like material extracted from the rat brain is distinct from authentic angiotensin II.
abstract: Specific radioimmunoassay and radioreceptor assay for angiotensin II (A II) were used for the possible identification of this peptide in the rat brain. An A II-like material (A II-LM) was detected with both assays applied to acidic extracts of various brain structures. The regional distribution of A II-LM was uneven, but absolute levels (in A II equivalents) could not be accurately determined, as they were highly dependent on the assay used. Partial purification of A II-LM by Sep-Pak C 18 chromatography and affinity chromatography using anti-A II antibodies bound to Ultrogel gave a compound coeluting with authentic A II in reverse-phase HPLC. However, gel filtration through Sephadex G-25 and TSK Spherogel 3000 SW as well as anion exchange HPLC demonstrated that A II-LM did not correspond to authentic A II. Partial characterization of A II-LM indicated that this compound was probably a peptide with an apparent molecular weight of 5,000-7,000 (instead of 1,046 for A II) and more polar but less positively charged than A II. Whether A II-LM is, in fact, the endogenous ligand of A II binding sites in brain remains an interesting hypothesis for further investigations.
authors.affiliation: INSERM Unité 288, Neurobiologie Cellulaire et Fonctionnelle, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Pohl
authors.forename: A
authors.initials: A
authors.lastname: Carayon
authors.forename: F
authors.initials: F
authors.lastname: Cesselin
authors.forename: M
authors.initials: M
authors.lastname: Hamon
mesh_terms: D000804:Angiotensin II / Q000032:analysis*; D000818:Animals; D001923:Brain Chemistry; D002531:Cerebellum / Q000032:analysis; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006624:Hippocampus / Q000032:analysis; D007668:Kidney / Q000032:analysis; D008297:Male; D011863:Radioimmunoassay; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
chemical_list: D000804:Angiotensin II