title: A receptor binding assay for endoxin in human urine.
abstract: Endoxin is an endogenous substance known to participate in the regulation of the sodium balance and hypertension. Its chemical nature remains elusive. Based on its capacity to specifically bind to Na-K ATPase receptors we describe a receptor assay for its measurement in human urine. The endoxin was extracted by methanol and desalted on a silicagel column with a mixture of chloroform-ethanol. Calibration curves have been established by the transformation of the weight of crude extract in actual content of active material expressed in nmol/l as calculated from Scatchard plots analysis. Normal values are given for subjects on regular salt diet. Changes in endoxin urinary elimination after an oral salt load are outlined.
mesh_terms: D001667:Binding, Competitive; D001798:Blood Proteins / Q000652:urine*; D002298:Cardenolides; D004077:Digoxin; D005260:Female; D006801:Humans; D008297:Male; D011786:Quality Control; D011869:Radioligand Assay; D012016:Reference Values; D012503:Saponins; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase