Characterization of High Specific Activity [16a-123I]Iodo-17 β-estradiol as an Estrogen Receptor-specific Radioligand Capable of Imaging Estrogen Receptor-positive Tumors

Edward J. Pavlik, Katherine Nelson, Holly H. Gallion, John R. van Nagell, Elvis S. Donaldson, W. J. Shih, Daniel E. Kenady, Jay A. Spicer, David F. Preston, Richard J. Baranczuk

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

lfa-(123I]iodo-17 β-estradiol (16α-[123I]Ea) has been characterized for use as a selective radioligand for estrogen receptor (ERc) that is capable of generating in situ images of ERc-positive tumors. High specific activity 16α-[l23I)E2 (7,500-10,000 Ci/mmol) was used in all determinations. Radiochemical purity was determined by thin layer chromatography, and the selectivity of radioligand for ERc was evaluated using size exclusion high performance liquid chromatography on ERc prepared from rodent uteri. Efficiencies of radioiodination approaching 100% were achieved, and excellent receptor selectivity was obtained even when the efficiency of radioiodination was as low as 10%. Low radiochemical purity was always associated with poor selectivity for ERc. No new radioligand species was generated during the course of radiodecay, however, reduced binding over time, even when increased activity was used to compensate for radiodecay, indicated that the formation of a radioinert competitor does occur. 16α-[I23I]E2 demonstrated stable, high affinity binding to ERc and was concentrated by ERc-positive tissues. After injecting 16α-[123I] E2 in vivo, images of ERc-containing tissues were obtained, including rabbit reproductive tract and dimethylbenzanthracene-induced tumors. The demonstrations of ERc selectivity and image formation both indicate that 16α-[123I)E2 should have promise as a useful new radiopharmaceutical for imaging ERc-positive cancers.

Original languageEnglish
Pages (from-to)7799-7805
Number of pages7
JournalCancer Research
Volume50
Issue number24
StatePublished - Dec 15 1990

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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