Mifepristone-d3 (Synonyms: RU486-d3; RU 38486-d3)

Mifepristone-d₃ is intended for use as an internal standard for the quantification of mifepristone by GC- or LC-MS. Mifepristone is an antagonist of glucocorticoid, progesterone, and androgen receptors (K_is = 0.1, 0.64, and 0.65 nM, respectively).^1,2,3 It is selective for these receptors over the mineralocorticoid receptor (MR), estrogen receptor α (ERα), and ERβ (K_is = 640, >200, and >750 nM, respectively).¹ In cell-based assays, mifepristone inhibits alkaline phosphatase activity stimulated by the progesterone receptor agonist R5020 as well as reporter transcription stimulated by either dexamethasone or R5020 (IC₅₀s = 7, 5.9, and 1.3 nM, respectively).³ It also inhibits synthetic androgen R1881-stimulated reporter transcription in a concentration-dependent manner.² Mifepristone (10 µM) inhibits growth of 4-OHT-resistant MCF-7 breast cancer cells in vitro.⁴ It also inhibits tumor growth in an SKOV3 ovarian cancer nude mouse xenograft model when administered at doses of 0.5 or 1 mg per day.⁵ Formulations containing mifepristone have been used for the induction of medical abortions.

1.von Gerldern, T.W., Tu, N., Kym, P.R., et al.Liver-selective glucocorticoid antagonists: A novel treatment for type 2 diabetesJ. Med. Chem.47(17)4213-4230(2004) 2.Song, L.-N., Coghlan, M.J., and Gelmann, E.P.Antiandrogen effects of mifepristone on coactivator and corepressor interactions with the androgen receptorMol. Endocrinol.18(1)70-85(2004) 3.Attardi, B.J., Burgenson, J., Hild, S.A., et al.In vitro antiprogestational/antiglucocorticoid activity and progestin and glucocorticoid receptor binding of the putative metabolites and synthetic derivatives of CDB-2914, CDB-4124, and mifepristoneJ. Steroid Biochem. Mol. Biol.88(3)277-288(2004) 4.Gaddy, V.T., Barrett, J.T., Delk, J.N., et al.Mifepristone induces growth arrest, caspase activation, and apoptosis of estrogen receptor-expressing, antiestrogen-resistant breast cancer cellsClinical Cancer Research105215-5225(2004) 5.Goyeneche, A.A., CarÓn, R.W., and Telleria, C.M.Mifepristone inhibits ovarian cancer cell growth in vitro and in vivoClin. Cancer Res.13(11)3370-3379(2007)