such as congestive heart failure cirrhosis of the liver and nephrotic syndrome and hypotension in a specific embodiment the ouabain resistant na u2014 k atpase is derived from a rodent an amphibian or a butterfly species for example a suitable ouabain resistant na u2014 k atpase can be derived from a mouse a rat a toad bufo marinus or a monarch butterfly danaus plexippus alternatively the ouabain resistant na u2014 k atpase can be obtained by converting or mutating an ouabain sensitive na u2014 k atpase into an ouabain resistant one the ouabain resistant na u2014 k atpase can be obtained by changing or substituting one or both border amino acid residues of the h1 h2 extracellular domain of u03b1 subunit of an ouabain sensitive na u2014 k atpase to a charged amino acid residue including a positively or negatively charged amino acid additional examples of mutations that confer ouabain resistance to an otherwise ouabain sensitive na u2014 k atpase is disclosed in lingrel et al the sodium pump bamberg and schoner ed pp 276 286 1994 the content of which is incorporated herein by reference in its entirety the nucleotide sequence for rat butterfly monarch danaus plexippus and toad bufo marinus u03b1 1 na u2014 k atpase is disclosed in.