Preparation of specific antibodies to catecholamines and L-3,4-dihydroxyphenylalanine. III. Preparation of antibody to epinephrine for radioimmunoassay.
Preparation of the antibody for radioimmunoassay [RIA] of epinephrine was examined and an antibody with proper titer was obtained. A procedure for RIA of epinephrine was developed by use of a membrane filter to separate bound and free hapten. The dose-response curves of analogs of epinephrine obtained by this method showed that the specificity of the antibody to epinephrine was sufficiently high: The 50% inhibition value of epinephrine was 1 pmol; those of metanephrine and synephrine, 80 pmol and those of norepinephrine and dopamine, 6 .times. 103 pmol. The antibody recognizes not only the side chain but also the catechol moiety of the hapten. The sensitivity of this RIA was high enough to determine 0.1 pmol of epinephrine. Bovine serum albumin and rabbit serum albumin were employed.