STUDIES ON THE SO-CALLED HEART HORMONE

Abstract

The effect on the perfused rabbit heart of extracts of all parts of the heart is found to be an augmentation of varying degree, often preceded or followed by a diminution of beat. This effect is somewhat inconstant and variable, but may be obtained from the extracts of the hearts of many different animals; e.g., calf extracts produce the greatest augmentation of the boat of the rabbit heart, and rabbit extracts the least. Relatively large amounts of extract must be used to obtain this augmentation. Similar effects, somewhat less marked, are obtained by the use of extracts of other tissues, such as striped and smooth muscle, liver, and lung. The effects of extracts of heart and other tissues are extremely like those of histamine. These results do not confirm the theory of a specific heart hormone, but rather support the view of a widely distributed substance occurring in most tissues, and possessing, in adequate concentration, an augmenting action on the heart.