Description_x000D_ General description_x000D_ Ouabain is a steroid hormone, naturally present in mammals._x000D_ Application_x000D_ Ouabain octahydrate has been used:_x000D_ • to determine the effect of salt and ammonia in the external environment on the rate of activity of Na+ /K+ in either silver or golden perch_x000D_ • in the basolateral compartment to induce maximal baseline short-circuit current in rat fetal distal lung epithelial (FDLE) cells_x000D_ • as an Na+/K+ ATPase inhibitor to study the relation between blister formation and adenosine triphosphate (ATP) dependent maintenance of plasma membrane homeostasis_x000D_ Biochem/physiol Actions_x000D_ Cardiac glycoside, inhibits Na(+)/K(+) ATPase, regulates transcription of MDR (increase, Pgp) and MRP (increase MRP1 and decrease CFTR, cyctic fibrosis transport receptor or cAMP-activated Cl- channel) genes, also alters localization of MRP1. Ouabain resistance is associated with appearance of Na(+)/K(+) ATPase isoforms with low binding affinity._x000D_ Ouabain has its specific binding site on integral proteins of the plasma membrane. Heart disease is treated using ouabain derivatives. Increased ouabain production is observed during exercise in humans. Abnormally high levels of ouabain are indicated in congestive heart failure and hypertension. Ouabain signalling affects intracellular calcium levels, which is known to activate nuclear factor κB (NFκB)._x000D_ Features and Benefits_x000D_ This compound is a featured product for ADME Tox research. Click here to discover more featured ADME Tox products. Learn more about bioactive small molecules for other areas of research at sigma.com/discover-bsm._x000D_ This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more._x000D_ Caution_x000D_ Aqueous solutions can be autoclaved._x000D_ Legal Information_x000D_ LOPAC is a registered trademark of Sigma-Aldrich Co. LLC