PREPARATION AND CHARACTERIZATION OF I-125 LABELED PROGESTERONE DERIVATIVES FOR THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR PROGESTERONE

Preparation and purification of radioiodinated progesterone derivative s for the development of a radioimmunoassay of progesterone is describ ed. We have standardized two procedures for preparing radioiodinated p rogesterone conjugate. In the first procedure I-125 labeled histamine was conjugated to progesterone 11alpha hemisuccinate by the mixed anhy dride method. In the second procedure, tyrosyl methyl ester was conjug ated to progesterone 11alpha hemisuccinate and iodination of the conju gate was carried out. Purification of the iodinated products was carri ed out by solvent extraction and thin layer chromatography techniques. The radiochemical purity of the tracers prepared by both methods were more than 95%. Labeled progesterone derivatives prepared were used fo r developing a radioimmunoassay procedure. The non-specific binding of the tracer was about 2-3%, while up to 80% binding could be obtained in the presence of excess antibody. The radioiodinated tracer could be used up to four months in the assay.