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OUABAIN RECEPTOR BINDING OF HYDROXYPROGESTERONE DERIVATIVES
Author(s) -
CHOW EDWIN,
KIM RYUNGSOON SONG,
LABELLA FRANK S.,
QUEEN GARY
Publication year - 1979
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1979.tb08686.x
Subject(s) - hydroxyprogesterone , ouabain , chemistry , receptor , endocrinology , pharmacology , medicine , biochemistry , biology , steroid , sodium , hormone , organic chemistry
1 A specific and sensitive radioreceptor assay has been devised which is based on high affinity, saturable binding of 9 n m [ 3 H]‐ouabain to the total particulate fraction isolated from dog heart. Ouabain and other cardiac glycosides, including the aglycones, were about equipotent in their ability to displace [ 3 H]‐ouabain from its receptor, the IC 50 s ranging from 10 to 30 n m . 2 The only other substances found to compete significantly in the assay were derivatives of hydroxy‐progesterone having a 17α‐acetate substituent: chlormadinone acetate, megestrol acetate, cyproterone acetate and medroxyprogesterone acetate, with IC 50 s of 2, 7.4, 9 and 21 μ m , respectively. Prednisolone‐3,20‐bisguanyl‐hydrazone, reported to have inotropic activity, gave an IC 50 of 6.4 μ m . Cyproterone‐17α‐OH was less active (IC 50 90 μ m ) than cyproterone‐17α‐acetate. 3 A large number of peptide and protein hormones, steroid hormones and their metabolites, amines, and drugs were inactive.