As with other organs of the body, antioxidant activity -- particularly glutathione -- plays a vital role in the kidneys. The kidneys are not unique in that oxidative stress, resulting from free radical activity, leads to problems of various kinds.
Speaking specifically of the kidneys, one article stated that "part of the oxidation burden originates in inadequacy of the body's own antioxidant enzymes." The article stated that diminished anti-oxidant levels, specifically glutathione and catalase, were the cause of oxidative stress in the kidneys, which led to other, even more significant problems.
The same article cited a study that tested the effect of the amino acid N-acetylcysteine (NAC), a precursor to glutathione, and its ability to prevent oxidative injury in the kidneys. The study showed that NAC effectively inhibited destructive oxidant response.
According to one researcher, kidney (or renal) toxicity is often caused by "exposure to heavy metals such as mercury, cadmium and lead." Studies have shown that the body detoxifies these subdstances primarily through gutathione-related enzymes. These glutathione enzymes have distinct distribution along the nephron in the kidneys, making them central to kidney detoxification and function.