THE SOURCE OF THE HEART GLYCOGEN

¹ The Department of Physiology, Biochemistry, and Pharmacology, University

1. By continuous administration of adrenaline (together with high mechanical work) the glycogen content of the dog's heart is rapidly lowered. When it has all been exhausted failure suddenly occurs.

2. When the administration of adrenaline is stopped short of failure, and when the glucose and lactate of the blood have also been reduced to low levels, there is no recovery of glycogen; glyconeogenesis therefore does not occur, or is relatively slow.

3. Addition of lactate after glycogen depletion by adrenaline, if the blood glucose is low, leads to no recovery of glycogen in two hours.

4. Addition of glucose after adrenaline depletion and with low blood lactate results in considerable restoration of heart glycogen in two hours. The heart glycogen is therefore formed from glucose.

5. Addition of both glucose and lactate to adrenaline-depleted hearts leads to a smaller glycogen formation than is obtained by addition of glucose alone. This is perhaps correlated with the fact that high lactate depresses the sugar usage of the heart.

6. Addition of either glucose or lactate, so as to give large concentrations of either in the blood prior to the addition of the adrenaline does not hinder the glycogen depletion caused by adrenaline.

The costs of the investigation were in part defrayed out of a grant from the Thomas Smythe Hughes Fund by the University of London to R. A. G., and of a grant from the Government Grants Committee of the Royal Society to J. Y. B. The authors wish to express their thanks for these two grants.