Changes in Content of Purine Nucleoside in Canine Myocardium during Coronary Occlusion

The use of a sensitive double-beam spectrophotometer and modifications in enzymatic assay techniques permitted the measurement of adenine nucleosides in extracts of canine left ventricle. In hearts not subjected to left coronary occlusion, adenosine content averaged 0.32 ± 0.04 (SE) nmole/g, increasing to an average of 1.82 ± 0.21 (SE) nmole/g after 15 seconds of coronary occlusion. The myocardial content of inosine plus hypoxanthine was 1.07 ± 0.21 (SE) nmole/g without coronary occlusion, rising to 1.98 ± 0.24 (SE) nmole/g after 15 seconds of coronary occlusion. Unlike the myocardial content of adenosine and inosine, the myocardial content of hypoxanthine did not appear to change during coronary occlusion.