Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.2 (NQO1)
 6,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of long-term GSH administration on aflatoxin B1 (AFB1)-induced carcinogenesis in the livers of male Wistar II rats was evaluated. No significant effect of an 11 months period of reduced glutathione (GSH) administration was observed concerning both the survival curve and the incidence of liver tumors. Liver tissues of all animals were bearing tumors or nodular lesions 24 months after AFB1 treatment, regardless of GSH treatment. The capacity of the GSH conjugation system was elevated in the liver tissue of AFB1-treated animals both by an increase of GSH content and an increase of the specific activities of several GSH S-transferase isoenzymes. Likewise the specific activities of GSH related enzymes as GSSG reductase and gamma-glutamyltransferase (gamma-GT) and the activity of the GSH independent detoxication system NAD(P)H:quinone oxidoreductase were increased in the AFB1-treated livers, there was no significant effect of GSH treatment. These results demonstrate that long-term GSH treatment has no effect on the survival of AFB1-pretreated male rats on the incidence of liver tumors and on the activities of drug metabolizing systems. The hepatic detoxication capacity 24 months after AFB1 treatment is elevated.
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PMID:Lack of effect of long-term glutathione administration on aflatoxin B1-induced hepatoma in male rats. 392 36

Biochemical and histochemical studies were conducted in aflatoxin B1-induced liver tumors in adult rainbow trout. Specific activities of the phase I enzymes, ethoxyresorufin-O-deethylase (EROD), microsomal and cytosolic epoxide hydrolase (mEH and cEH), aldehyde dehydrogenase (ALDH) and DT-diaphorase, and the phase II enzymes, gamma-glutamyltransferase (gamma-GT), glutathione transferase (GST) and uridine diphosphoglucuronyl transferase (UDPGT) were measured. Cryostat sections of tumor and surrounding liver from the same cohorts were analyzed immunohistochemically for cytochrome P450IA1 and histochemically for ALDH (benzaldehyde and hexanal), DT-diaphorase, gamma-GT and uridine diphosphoglucuronyl dehydrogenase (UDPGdH). In tumor tissues, the largest biochemical changes were found with benzaldehyde dehydrogenase, where activity increased from undetectable levels to 7.4 nmol/min/mg protein, and gamma-GT, where activity increased 12-fold over controls. Increases in other enzymes ranged from 1.26 to 2.84 times that of control liver, except EROD, which decreased, and cEH and mEH, which were unchanged. Histochemical analyses showed the induction of ALDH, gamma-GT, DT-diaphorase and UDPGdH, and the depression of cytochrome P450IA1 in hepatic neoplasms. In addition, marker enzyme histochemistry of neoplasms revealed heterogeneous populations of hepatocytes and absence of necrotic areas.
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PMID:Biochemical and histochemical properties of hepatic tumors of rainbow trout, Oncorhynchus mykiss. 809 46

Reduction of the blue dye resazurin to pink resorufin is used to estimate the concentration of metabolically active spermatozoa in semen samples. In order to quantify the reduction of resazurin, a spectrophotometric method was developed measuring the change from blue to pink in the butanol extracted colour. The biochemical mechanisms involved in the reduction of resazurin by motile spermatozoa and seminal plasma were investigated. Addition of NADH + H+ to sperm suspension or seminal plasma increased the reduction of resazurin. The reduction reaction was inhibited by high concentrations of dicoumarol, a specific inhibitor of the diaphorase enzyme, in a dose-dependent manner. It is suggested that the sperm diaphorase enzyme transfers electrons from NADH + H+ to resazurin, reducing it to resorufin. The degree of resazurin reduction was strongly correlated with the concentration of motile spermatozoa recovered from the 90% Percoll fraction (r = 0.98, p < 0.001). A positive correlation was also found between the reducing capacity of seminal plasma (n = 62) on the one hand, and sperm concentration (r = 0.72, p < 0.0001), progressive motility (r = 0.45, p < 0.01), normal morphology (r = 0.50, p < 0.01), and gamma-glutamyltransferase (r = 0.36, p < 0.05) on the other hand. These findings, together with our previous observations that the reduction reaction is inhibited by reactive oxygen species and polymorphonuclear white blood cells, increase our understanding of the biochemical basis of the resazurin test and may provide better insight into the interpretation of this test.
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PMID:The correlates and alleged biochemical background of the resazurin reduction test in semen. 980 45

This study investigated the effect of protein malnutrition on metabolism and toxicity of cisplatin (CP), 5-fluorouracil (FU) and mitomycin C (MMC) in rat stomach. Weanling male Wistar rats received a normal (24%) or low (2.5%) protein diet for 28 days and were allocated into: normally-fed control, protein-malnourished control (PM), 3 normally-fed drug-treated groups and 3 protein-malnourished drug-treated groups (PM-CP, PM-FU and PM-MMC). Cisplatin and MMC were injected intraperitoneally (8 mg/kg on day 26 and 1 mg/kg/day for 7 days, respectively). 5-Fluorouracil was given orally (50 mg/kg/day for 5 days). Compared with normally-fed counterparts, PM-CP rats exhibited higher glutathione S-transferase, aminopeptidase N and cysteine S-conjugate beta-lyase (CCBL) and lower gamma-glutamyltransferase activities, PM-FU rats exhibited decreased dihydropyrimidine dehydrogenase and cytochrome P450 1A1/2 activities and PM-MMC rats showed higher quinone reductase and depleted xanthine oxidase activities. Protein-malnourished drug-treated groups exhibited exacerbated gastrotoxicity, relative to normally-fed counterparts, manifested by lower mucus levels, higher permeability and histopathological deterioration, along with increased oxidative stress in PM-CP rats and exaggerated prostaglandin E2 production in PM-MMC rats. Conclusively, protein malnutrition alters CP, FU and MMC metabolism in rat stomach by enhancing CCBL pathway for CP activation, delaying FU elimination and activating two-electron reduction of MMC, potentiating their gastrotoxicity.
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PMID:Effect of protein malnutrition on the metabolism and toxicity of cisplatin, 5-fluorouracil and mitomycin C in rat stomach. 2345 48