Proscillaridin A Immunoreactivity: Its Purification, Transport in Blood By A Specific Binding Protein And Its Correlation With Blood Pressure

Abstract

A material crossreacting with antibodies against the bufadienolide proscillaridin A and inhibiting the sodium pump was found in human blood plasma. The concentration of the material with a retention time similar to ouabain in a reversed phase HPLC correlated to systolic blood pressure and pulse pressure. Affinity purification of this compound from bovine adrenals resulted in the isolation of a compound with molecular mass of 600 Da that was not identical with ouabain

Consistent with the postulate that endogenous ouabain and proscillaridin A immunoreactivities may belong to a new class of cardiotonic steroid hormones, a protein of Mr = 60 kDa has been found in bovine serum by affinity-labeling with N-hydroxysuccimidyl digoxigenin-3-O-methylcarbonyl-aminocaproate

Key Words:

• Endogenous digitalis-like factor
• proscillaridin A immunoreactivity
• ouabain immunoreactivity
• sodium pump
• cardiac glycoside binding globulin