CHORIONUC GONADOTROPIC HORMONE BY OVARIAN CARCINOMA

(HCG) with 1—2atomsof radioactiveiodine does not affect the biological, immunological, and physio chemical behavior of the hormone (1). In the rodent the ovary has been demonstrated to concentrate HCG more than any other organ. Labeled albumin or 131! are not concentrated by the ovary even when. animals are stimulated simultaneously with unlabeled HCG (1,2). When increasing doses of ‘311-HCG, 131!.. albumin, and 1311-sodiumare injected, a concomitant increase in ovarian radioactivity is observed only in the animals receiving the labeled HCG (3).• When antiserum to HCG is injected 5 min before 1311-HCG, the labeled hormone becomes bound to the antiserum as a hormone-antihormone complex and is not concentrated by the ovary. Autoradiogra phy of histological sections of ovary after 131J.. labeled HCG administration in vivo reveals that the radioactivity is confined mainly to the follicular envelope, theca cells, and struma (4). We wish to report that ‘251-labeledHCG concen trates as well in theca cell carcinoma of the ovary as in the normal ovary. These findings have stimulated us to investigate the possible use of 1311-HCG for diagnosis of this lesion by in vivo scanning tech niques. MATERIALS AND METHODS Hormone procurement. A highly purified prepara tion of HC