THE USAGE OF PYRUVIC ACID BY THE DOG'S HEART

¹ Department of Physiology, Pharmacology, and Biochemistry, University College, London

1. No change occurs in sodium pyruvate which is added to blood and kept at 37°C. for some hours.

2. When sodium pyruvate is added to the circuit of the heart-lung or heart-oxygenator preparation, its effects upon the heart are similar to those of lactate. It is toxic in concentrations of about 150 mg./100 c.c.

3. Under the conditions described, pyruvic acid does not form heart glycogen.

4. Large amounts of pyruvic acid are used by the heart and the rate of usage is related to the concentration of pyruvate in the blood. The usage was not appreciably affected by variations in blood sugar or lactate, by iodoacetate (1: 10,000), vitamin B₁, or adrenaline.

5. Some preliminary experiments on the effect of pyruvate on the oxygen usage of the heart-lung preparation are described, and the fate of the pyruvate used by the heart is discussed.

The authors wish to thank Professor C. Lovatt Evans, who collaborated in part of the work, for his helpful advice and criticism throughout, and for the generous facilities afforded.

The costs were in part defrayed by a grant made to R. A. G. from the Thomas Smythe Hughes Fund by the University of London, to whom the authors are indebted.