Monkeys are widely used as a primate model to study drug metabolism because they generally show a metabolic pattern similar to humans. However, the paucity of information on cytochrome P450 (P450) genes has hampered a deep understanding of drug metabolism in the monkey. In this study, we report identification of the CYP2C76 cDNA newly identified in cynomolgus monkey and characterization of this CYP2C along with cynomolgus CYP2C20, CYP2C43, and CYP2C75. The CYP2C76 cDNA contains the open reading frame encoding a protein of 489 amino acids that are only approximately 80% identical to any human or monkey P450 cDNAs. Gene and protein expression of CYP2C76 was confirmed in the liver of cynomolgus and rhesus monkeys but not in humans or the great apes. Moreover, CYP2C76 is located at the end of the CYP2C gene cluster in the monkey genome, the region of which corresponds to the intergenic region adjacent to the CYP2C cluster in the human genome, strongly indicating that this gene does not have the ortholog in humans. Among the four CYP2C genes expressing predominantly in the liver, the expression level of CYP2C76 was the greatest, suggesting that CYP2C76 is a major CYP2C in the monkey liver. Assays for the capacity of CYP2C76 to metabolize drugs using several substrates typical for human CYP2Cs revealed that CYP2C76 showed unique metabolic activity. These results suggest that CYP2C76 contributes to overall drug-metabolizing activity in the monkey liver and might account for species difference occasionally seen in drug metabolism between monkeys and humans.Cytochrome P450s (P450s) are one of the most important drug-metabolizing enzymes and form a superfamily consisting of a large number of subfamilies (Nelson et al., 1996(Nelson et al., , 2004. The cDNA sequences encoding P450s have been reported for many species of not only mammals but also birds, insects, plants, bacteria, and others (see http://drnelson. utmem.edu/CytochromeP450.html). In humans, 57 functional genes have been identified to date (Nelson et al., 2004). The human CYP2C subfamily, comprising CYP2C8, CYP2C9, CYP2C18, and CYP2C19, is essential in metabolizing approximately 20% of all prescribed drugs, including tolbutamide, phenytoin, warfarin, and ibuprofen (Goldstein, 2001). The CYP2C subfamily consists of multiple members in each mammalian species, including 15 in mice, 12 in rats, and 9 in rabbits (for the latest information, see http://drnelson.utmem.edu/CytochromeP450.html). Between humans and rodents, the number of the subfamily members is different, and none of the CYP2Cs seems to show a clear orthologous relationship between the two species, suggesting that the data from rodents must be cautiously interpreted and extrapolated to humans (Nelson et al., 2004).For monkeys, which generally mean Old or New World monkeys, three CYP2C cDNAs have been identified in the macaque and cynomolgus (Macaca fascicularis) and rhesus (Macaca mulatta) monkeys. Two sequences have been published including cynomolgus CYP2C20 (Komori et al., 1992) and rhesus CYP...

Objective. Tissue hypoxia is closely associated with arthritis pathogenesis, and extracellular high mobility group box chromosomal protein 1 (HMGB-1) released from injured cells also has a role in arthritis development. This study was thus undertaken to investigate the hypothesis that extracellular HMGB-1 may be a coupling factor between hypoxia and inflammation in arthritis.Methods. Concentrations of tumor necrosis factor ␣, interleukin-6, vascular endothelial growth factor, lactic acid, lactate dehydrogenase, and HMGB-1 were measured in synovial fluid (SF) samples from patients with inflammatory arthropathy (rheumatoid arthritis and pseudogout) and patients with noninflammatory arthropathy (osteoarthritis). The localization of tissue hypoxia and HMGB-1 was also examined in animal models of collagen-induced arthritis (CIA). In cellbased experiments, the effects of hypoxia on HMGB-1 release and its associated cellular events (i.e., protein distribution and cell viability) were studied.Results. In SF samples from patients with HMGB-1-associated inflammatory arthropathy (i.e., samples with HMGB-1 levels >2 SD above the mean level in samples from patients with noninflammatory arthropathy), concentrations of HMGB-1 were significantly correlated with those of lactic acid, a marker of tissue hypoxia. In CIA models in which the pathologic phenotype could be attenuated by HMGB-1 neutralization, colocalization of HMGB-1 with tissue hypoxia in arthritis lesions was also observed. In cell-based experiments, hypoxia induced significantly increased levels of extracellular HMGB-1 by the cellular processes of secretion and/or apoptosis-associated release, which was much more prominent than the protein release in necrotic cell injury potentiated by oxidative stress.Conclusion. These findings indicate that tissue hypoxia and its resultant extracellular HMGB-1 might play an important role in the development of arthritis.High mobility group box chromosomal protein 1 (HMGB-1) is a nuclear architectural protein that is released from necrotic cells (1) and/or secreted from activated macrophages (2,3). It has been identified as a mediator of endotoxin-induced lethality (2,4) and a causative factor in arthritis (3,5-7), acting, at least in part, as a proinflammatory cytokine (1-11). Engagement of the receptor for advanced glycation end products (RAGE) by extracellular HMGB-1 triggers activation of proinflammatory signaling pathways (10,11), such as those resulting in elaboration of reactive oxygen inter-

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