Glutathione redox system in oxidative lung injury

Glutathione (GSH) is a ubiquitous intracellular thiol present in all tissue s, including lung. Besides maintaining cellular integrity by creating a red uced environment, GSH has multiple functions, including detoxification of x enobiotics, synthesis of proteins, nucleic acids, and leukotrienes. Present in high concentrations in bronchoalveolar lavage fluid (BALF), GSH provide s protection to the lung from oxidative injury induced by different endogen ous or exogenous pulmonary toxicants. Its depletion in the lung has been as sociated with the increased risk of lung damage and disease. The redox syst em of GSH consists of primary and secondary antioxidants, including glutath ione peroxidase (GPx), glutathione reductase (GR), glutathione 6-transferas e (GST), and glucose 6-phosphate dehydrogenase (G6PD). Alterations in the a ctivities of these enzymes may reflect reduced cellular defense and may ser ve as surrogate markers of many lung diseases. As GSH is also involved in t he regulation of expression of protooncogenes and apoptosis (programmed cel l death), the development of diseases such as cancer and human immune defic iency may be affected by depleting or elevating cellular GSH levels. Exogen ous delivery of GSH or its precursor N-acetyl cysteine (NAC) is being used as chemotherapeutic approach.