19] Strategies for measurement of angiotensin and bradykinin peptides and their metabolites in central nervous system and other tissues

Abstract

This chapter describes strategies for measurement of angiotensin and bradykinin peptides and their metabolites in central nervous system and other tissues. N terminal directed RIA is established for the measurement of angiotensin and bradykinin peptides and their C-terminal truncated metabolites. To raise N terminal-directed antisera to angiotensin peptides Asn, Val-Ang II are acetylated at the N terminus and coupled via the C terminus for immunization, they readily achieved N terminal-directed antisera. This result suggests that acetylation of the N terminus of a peptide renders the N terminus more immunogenic. Separation of acetylated peptides is performed by high-performance liquid chromatography. It is suggested that measurement of peptides in biological samples requires the prevention of peptide generation and metabolism during processing of the sample. In general, peptide recoveries approximate 40–50%. A number of different approaches are used to validate the methodology.