Transmural distribution of 5'-nucleotidase and of adenosine deaminase enzyme activities in the wall of the normal rat left ventricle.

The transmural distributions of adenosine metabolizing enzymes (5'-nucleotidase and adenosine deaminase) were examined in normal rat hearts. It was found that the total activities of both enzymes vary in a biphasic manner across the left ventricular wall, such that the ratio of 5'-nucleotidase to adenosine deaminase is at a minimum near the midmyocardium.