ORG-2058 as a ligand in the assay of progesterone receptor in breast cancer

Yoav Sharoni, Bianca Feldman, Noga Karny, Joseph Levy

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Tritiated [(16α-ethyl-21-hydroxy-19-nor-pregn-4-ene-3, 20-dione)-6,7-3H] (ORG-2058) and 17,21-dimethyl-19-nor-pregna-4,9-diene-3,20-dione (R5020) were compared as ligands in the assay of progesterone receptor in human of and rat breast tumors. We found that ORG-2058 is a better ligand because its low nonspecific binding. Most of the nonspecific binding of the other ligand R5020, is to proteins which bind corticosteroids. In cancerous tissue ORG-2058 binds to progesterone receptor linearly in a range of protein concentrations which are normally used in the receptor assay. On the other hand, R5020 exhibits binding linearity over a narrower protein concentration in many tumor biopsies, which may cause severe limitation in the assay procedure or frequent underestimation of receptor content.

Original languageEnglish
Pages (from-to)419-426
Number of pages8
Issue number5-6
StatePublished - 1 Jan 1986

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology
  • Pharmacology
  • Clinical Biochemistry
  • Organic Chemistry


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