Endothelial arginase II responds to pharmacological inhibition by elevation in protein level.

Arginase is an enzyme which converts arginine to ornithine and urea. Recently, arginase has been implicated in many physiological and pathological processes including vascular diseases. Inhibition of arginase activity by pharmacological inhibitors is a useful tool to study the biology of arginases and their possible role in therapy. There are several arginase-specific inhibitors commercially available. Herein, we show that some of these inhibitors lead to an increase in arginase II protein level and activity. These effects should be anticipated when these inhibitors are in use or during the testing of new arginase inhibitors.