标题：Properties of Novel Anti-digoxin Antisera in Radioimmunoassay Using Homologous and Site Heterologous Tritium-Labeled Antigens Involving a [3H]-Leucine Moiety
摘要：The specificities of antisera against digoxin C-3′ or C-3″ hemisuccinate–bovine serum albumin (BSA) conjugate were assessed by cross-reactivity studies with digoxin metabolites by radioimmunoassay (RIA) using the homologous and the site heterologous tritium-labeled antigens. One of the tracers used was digoxin 3′-hemisuccinyl-[3H]-leucine; the other was digoxin 3″-hemisuccinyl-[3H]-leucine, which had been prepared from digoxin 3″-hemisuccinate. When the tracer with [3H]-leucine at the C-3′ position was used, antisera (I-1, I-3) elicited by digoxin 3′-hemisuccinate–BSA conjugate showed the following cross-reactivity: digoxigenin bisdigitoxoside (0.34%, 76%), digoxigenin monodigitoxoside (0.11%, 65%), digoxigenin (0.02%, 26%) and dihydrodigoxin (9.4%, 1.2%). However, when using the homologous antigen, antiserum (I-1) was highly specific against the digitoxose chain. When the site heterologous antigen, digoxin 3″-hemisuccinyl-[3H]-leucine was combined, this antiserum showed high cross-reactivity to digoxin degradation products. This digoxin RIA using antiserum (I-1) with the homologous antigen measures unmetabolized digoxin. On the other hand, the RIA system using antiserum (I-3) with the homologous antigen had cross-reactivity with the metabolites in accordance with their relative cardio-activities, so this system would be useful in therapeutic drug monitoring of digoxin.
关键词：digoxin;anti-digoxin antiserum;radioimmunoassay (RIA);digoxin 3′-hemisuccinate–bovine serum albumin conjugate;digoxin 3″-hemisuccinyl-[3H]-leucine
