ABSTRACT
Nitric oxide is a free radical gas and perhaps the smallest known biological mes senger and cytotoxic mediator. Since its discovery more than a decade ago as an endothelium-derived relaxing factor (EDRF) (1-3), nitric oxide has been im plicated in many physiological and pathophysiological processes (4-10). Re cently, considerable attention has focused on the role of nitric oxide in the regu lation of cell growth. In earlier reports, nitric oxide was shown to inhibit cell growth, a process that was associated with suppression of DNA synthesis and, eventually, cell death (11). It is now well established that in mammalian cells, death can occur via multiple pathways including necrosis and apoptosis, and an emerging literature indicates that nitric oxide can induce cell death by both path ways. The present review will focus on the regulation of apoptosis by nitric ox ide and its oxidation products.
