Abstract
In the previous papers (1-4), it was shown that, when digitoxin is given into the animals suffering either from circulatory disturbances in liver or from liver damages, not only the lethal dose decreases but also the characteristic changes due to digitoxin in the electrocardiogram, i.e. the prolonged PQ-interval and the depressed ST-segment, appear to a lower degree, suggesting that there is an intimate relationship between the cardiac action of digitoxin and an activity of liver. In other words, these findings would imply that digitoxin undergoes a change in its molecular level or an effective substance (or substances) is added during the passage of digitoxin in liver and thus the potentiation of the cardiac action of digitoxin in question takes place. The purpose of the present study is to confirm the p revious results more precisely in a simpler system, using isolated liver of guinea pig, and to determine the nature of the above ‘liver-factor’ potentiating the cardiac action of digitoxin, which appears in connexion with the passage of digitoxin in liver.
