Development of a homologous iodine-125 labelled progesterone radioimmunoassay system

Detailed procedure description of an iodinated progesterone radioimmunoassay system development is reported. Immunization regime with progesterone 11 α-hemisuccinate: BSA gave 1:6000 antibody titre within a period of 6 months. Minimal amount of the immunogen was spent to obtain a stock of the antiserum. Conjugation of progesterone 11 α-hemisuccinate to tyrosine methyl ester using the isobutyl-chloroformate reaction gave a product with less patch to patch variations in tracer characteristics. At home radioiodination with 125I reduced the expenses drastically and resulted in extended tracer shelf life (up to 3 months). The use of the second antibody method of separating bound from free hormone proved to be more convenient and brought the progesterone radioimmunoassay system to routine work