Preparation and purification of estriol, estradiol, and progesterone labeled with radioactive iodine.

Steroids labeled with radioactive isotopes are useful tracers for radio-immunoassay and for in vivo nuclear medecine purposes. We here report and discuss methods for direct labeling of the steroids estriol, estradiol, and progesterone with radioiodine-125 or -131. The purification procedure and some chemical and physical properties of the purified labeled materials are referred to and discussed.