抄録
The substance of retarding heart function was isolated by the lead acetate method from bovine heart muscle and then purified by alumina column chromatography and charcol treatment. This aqueous solution was pH 5.4 to 5.6 and possessed the remarkable action of retarding heart function. This solution affected normal heart nearly according to doses by Yagi-Straub perfusion method. On other hand, different result was observed on the heart which was weakened with chloralhydrate, i. e., this substance had promoting action on heart pretreated with chloralhydrate. The heart sensitized by the preadministration a little amount of this substance received hardly the action of chloralhydrate. One per cent solution of this substance had a stronger uterus contracting activity than 0.2 I. U. per cc solution of oxytocin. As for the depressor action, it played as a vasodilator of peripheral blood-vessel. LD50 was 0.002985±0.0004342g per mouse body weight (g) at a fiducial probability of 0.95.
