SUBCELLULAR DISTRIBUTION OF ³H-DIGITOXIN AND ITS METABOLITES IN THE HEARTS OF THE CATS WITH A HYPERSENSITIVITY TO THE DRUG

Abstract

To clarify the cause of hypersensitivity to digitoxin, an experiment was carried out with cats. The most potent hypersensitivity to digitoxin has been observed 48 hr after the injection of a loading dose. However, 1 hr after this injection, the cats failed to show the hypersensitivity. One, 24 and 48 hr after the injection of ³H-digitoxin, the contents of digitoxin and its metabolites in subcellular fractions of hearts were measured. Digitoxin contents in microsomal fractions 48 hr after the injection only slightly decreased, while those in mitochondrial and nuclear fractions markedly decreased as compared with the check at 1 hr. An increase of sodium ions and a decrease of potassium ions in the hearts were seen 48 hr after the injection. These facts may be related to the cause of hypersensitivity.