BUFODIENOLIDES AS ENDOGENOUS NA-ATPASE INHIBITORS - BIOSYNTHESIS IN BOVINE AND RAT ADRENALS(,K+)

The biosynthesis of digitalis-like compounds (DLC) was determined in b ovine and rat adrenal homogenates by following changes in the concentr ation of DLC using three independent sensitive bioassays: inhibition o f [H-3]-ouabain binding to red blood cells and competitive ouabain and bufalin ELISA. The amounts of DLC in bovine and rat adrenal homogenat es, as measured by the two first bioassays, increased with time when t he mixtures were incubated under tissue culture conditions. These resu lts suggest that Na+, K+-ATPase inhibitors which interact with ouabain antibodies, but not those which interact with bufalin antibodies, are synthesized in bovine and rat adrenals.