Uptake of radiolabeled estradiol by the canine adrenal

Tritiated estradiol injected intravenously into 11 mongrel dogs sacrificed at 3, 7, 10, 17, and 60 min showed maximum uptake in the adrenal gland at 3-7 min. The concentrations of radioactivity in the adrenal in percent dose per gram equaled that from 131I-19-iodocholesterol. If a 131I-estradiol could be synthesized that would concentrate similarly in the adrenal, it would offer the advantage of almost instantaneous imaging after the tracer injection and a lower radiation dose.