title: Saturable binding of [3H]-promegestone in sheep liver cytosol is not to receptors for progesterone or glucocorticoids.
abstract: Saturable, high affinity binding of [3H]-promegestone has been observed in sheep liver cytosol. In two tissues specimens the Kd values were 5.9 and 6.3 nmol/l, and the concentrations of binding sites were 84.5 and 66.2 pmol/g wet tissue respectively. The synthetic steroids methyltrienolone and ORG 2058 were capable of some degree of competition. Progesterone was a weak competitor; cortisol, dexamethasone and testosterone were ineffective. Bound promegestone in liver cytosol was taken up by liver nuclei, but not by sheep uterine nuclei. These promegestone-binding sites are neither progesterone or glucocorticoid receptors.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D005260:Female; D008099:Liver / Q000378:metabolism*; D009649:Norpregnadienes / Q000378:metabolism*; D011397:Promegestone / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D012756:Sheep; D013379:Substrate Specificity; D014599:Uterus / Q000378:metabolism
chemical_list: D009649:Norpregnadienes; D011965:Receptors, Glucocorticoid; D011980:Receptors, Progesterone; D011987:Receptors, Steroid; D011397:Promegestone