COMPARISON OF THE DISTRIBUTION OF RADIOIODINATED DI-HYDROXYPHENYLETHYLENE AND TRI-HYDROXYPHENYLETHYLENE ESTROGENS IN THE IMMATURE FEMALE RAT

The uptake, retention and tissue to blood ratios of two non-steroidal, I-125-labeled iodoestrogens, an iodotrihydroxyphenylethylene, 2-bis(4 -hydroxyphenyl)-2-(3-hydroxyphenyl)ethylene and an iododihydroxyphenyl ethylene, 2-iodo-1,1-bis(4-hydroxyphenyl)-2-phenylethylene, were compa red after intraperitoneal injection in immature female rats. The iodot rihydroxyphenylethylene showed an unexpectedly prolonged specific rete ntion in estrogen target tissue, lasting up to 72 h. It was rapidly cl eared from blood and non-target tissues so that uterus or ovary to blo od ratios of greater than 100 were seen at 2 and 3 days. This iodotrih ydroxyphenylethylene may have clinical potential for estrogen receptor -containing cancers.