title: Renal aldosterone receptors: studies with (3H)aldosterone and the anti-mineralocorticoid (3H)spirolactone (SC-26304).
abstract: In vivo, a spirolactone (SC-26304) inhibited the effects of aldosterone on urinary K(+):Na(+) ratios and the binding of [(3)H]aldosterone to renal cytoplasmic and nuclear receptors. Cytoplasmic binding of [(3)H]aldosterone and [(3)H]spirolactone (SC-26304) was similar in magnitude and involved the same set of sites. Under three sets of conditions-(i) in the intact rat, (ii) in kidney slices, and (iii) in reconstitution studies (mixing prelabeled cytoplasm with either purified renal nuclei or chromatin), [(3)H]spirolactone (SC-26304) did not yield specific nuclear complexes in contrast to the reproducible generation of these complexes with [(3)H]aldosterone. In glycerol density gradients, cytoplasmic [(3)H]aldosterone receptor complexes sedimented at 8.5 S and 4 S in low concentrations of salt and at 4.5 S in high concentrations of salt. Cytoplasmic [(3)H]spirolactone (SC-26304) receptor complexes sedimented at 3 S in low concentrations of salt and 4 S in high concentrations of salt. These results are discussed in terms of an allosteric model of the receptor system.
mesh_terms: D000315:Adrenalectomy; D000450:Aldosterone / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001667:Binding, Competitive; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D003593:Cytoplasm / Q000378:metabolism; D066298:In Vitro Techniques; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007677:Kidney Function Tests; D007783:Lactones / Q000494:pharmacology; D000451:Mineralocorticoid Receptor Antagonists; D011485:Protein Binding; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects*; D013141:Spiro Compounds / Q000494:pharmacology*; D013148:Spironolactone / Q000031:analogs & derivatives; D014316:Tritium
chemical_list: D007783:Lactones; D000451:Mineralocorticoid Receptor Antagonists; D011956:Receptors, Cell Surface; D013141:Spiro Compounds; D014316:Tritium; D013148:Spironolactone; C006286:SC 26304; D000450:Aldosterone