we assay a 1-ml plasma sample containing angiotensin ii ( 103 pg by radioimmunoassay ) for the hormone by the following sequence of steps : add 125i-labeled val5-angiotensin ii as an internal standard , extract on a c18 sep pak column , extract on an antibody affinity column , label the extract with an 125i bolton-hunter reagent , separate on a bio gel p2 column , and repetitively separate on a reversed-phase `` '' high-performance '' '' liquid-chromatographic column , detecting the eluting compounds by counting radioactivity .
C0003018
angiotensin
C0003009
angiotensin ii