PREPARATION OF I-125 LABELED TESTOSTERONE DERIVATIVES FOR USE IN RADIOIMMUNOASSAYS

Three different radiotracers of testosterone incorporating I-125 at po sition 3 or 19 were prepared and tested for usability in radioimmunoas says employing the antisera raised at our laboratory. Histamine was ra dioiodinated and conjugated to suitable testosterone derivatives. On o ptimization, tracers with high purity, good immunoreactivity and long stability could be obtained for all the three tracers. However, the us ability of a tracer will also depend on the antiserum used and this wa s also demonstrated using different pairs of antisera and tracers.