Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protective effect of butyrate against hyperoxia was found with adult rat pulmonary artery smooth muscle cells. Butyrate (5mM) when added just prior to the hyperoxic exposure (95%) markedly decreased lactate dehydrogenase release from cells during 68 hours of exposure (22% release with butyrate versus 98% without). The uptake and reduction of a tetrazolium compound as another index of cell viability also showed similar improvement with butyrate. Butyrate was associated with a striking increase of catalase to three times the control in the air exposed group while GSH content and the activities of superoxide dismutase and glutathione peroxidase were not significantly changed. In the groups exposed to hyperoxia alone, both enzyme activities were decreased compared to the air exposed controls. When butyrate was present with hyperoxia, the superoxide dismutase was maintained closer to the air exposed control values and the catalase activity remained nearly twice as high as the air exposed control cells. These results suggest that butyrate protects rat pulmonary artery smooth muscle cells from hyperoxia by increasing catalase activity which may help to preserve superoxide dismutase activity. This may be a good model to determine the biological significance of catalase and its interrelationships with other antioxidant systems within the cell.
 ...
PMID:Butyrate increases catalase activity and protects rat pulmonary artery smooth muscle cells against hyperoxia. 259 Jan 95

The effects of oxidative stress caused by hyperoxia or administration of the redox active compound diquat were studied in isolated hepatocytes, and the relative contribution of lipid peroxidation, glutathione (GSH) depletion, and NADPH oxidation to the cytotoxicity of active oxygen species was investigated. The redox cycling of diquat occurred primarily in the microsomal fraction since diquat was found not to penetrate into the mitochondria. Depletion of intracellular GSH by pretreatment of the animals with diethyl maleate promoted lipid peroxidation and sensitized the cells to oxidative stress. Diquat toxicity was also greatly enhanced when glutathione reductase was inhibited by pretreatment of the cells with 1,3-bis(2-chloroethyl)-1-nitrosourea. Despite extensive lipid peroxidation, loss of cell viability was not observed, with either hyperoxia or diquat, until the GSH level had fallen below approximately 6 nmol/10(6) cells. The iron chelator desferrioxamine provided complete protection against both diquat-induced lipid peroxidation and loss of cell viability. In contrast, the antioxidant alpha-tocopherol inhibited lipid peroxidation but provided only partial protection from toxicity. The hydroxyl radical scavenger alpha-keto-gamma-methiol butyric acid, finally, also provided partial protection against diquat toxicity but had no effect on lipid peroxidation. The results indicate that there is a critical GSH level above which cell death due to oxidative stress is not observed. As long as the glutathione peroxidase - glutathione reductase system is unaffected, even relatively low amounts of GSH can protect the cells by supporting glutathione peroxidase-mediated metabolism of H2O2 and lipid hydroperoxides.
 ...
PMID:Effects of oxidative stress caused by hyperoxia and diquat. A study in isolated hepatocytes. 350 39