O-2 UPTAKE IN PERIPORTAL AND PERICENTRAL REGIONS OF LIVER LOBULE IN PERFUSED LIVER
O-2 UPTAKE IN PERIPORTAL AND PERICENTRAL REGIONS OF LIVER LOBULE IN PERFUSED LIVER
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DOI：
10.1152/ajpgi.1986.250.6.g800
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发表时间：
1986-06-01
影响因子：
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通讯作者：
THURMAN, RG
中科院分区：
文献类型：
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作者：
MATSUMURA, T;KAUFFMAN, FC;THURMAN, RG
当输入氧浓度发生变化时，灌注的肝脏对氧的摄取明显高于引起NADH减少的水平。门静脉周围的最大氧摄取率是门静脉周围的2 - 3倍。8 .mu。摩尔.cntdot。g - 1 .cntdot级。h;O2浓度= 478 +-。37 .mu。M)比中心周围区域(59 .+-。5 .mu。摩尔.cntdot。g - 1 .cntdot级。h;O2浓度= 263 +-。21 .mu.M);然而，一半最大氧摄取所需的氧浓度是相似的。20 .mu。M)在这两个方面。白术苷、抗霉素A或KCN的输注抑制了这两个区域的O2摄取50-85%，表明这两个区域的O2摄取在很大程度上依赖于线粒体电子传递。门静脉周围和中央周围显微解剖标本中ATP和ADP及ATP:ADP的含量相似。相反，当肝脏逆行灌注时，中央周围的氧摄取是门静脉周围的2 - 3倍。当电极通过微操作器穿过肝小叶时，最大氧摄取率与局部氧浓度相关，而与流动方向无关。中心周围区域较低的氧摄取率没有明显改变，已知的药物输注解偶联氧化磷酸化（DNP），增加ADP供应（果糖），或增加NADH氧化还原状态（乙醇或辛酸盐）。这些数据与假设一致，即在灌注的肝脏中，最大的氧摄取速率在一定程度上受到远高于细胞色素氧化酶对氧的Km的氧浓度的调节。
O2 uptake by the perfused liver decreased at O2 concentrations considerably higher than levels that caused NADH reduction when the input O2 concentration was varied. The maximal rate of O2 uptake was two- to threefold higher in periportal (137 .+-. 8 .mu.mol .cntdot. g-1 .cntdot. h-1; O2 concentration = 478 .+-. 37 .mu.M) than pericentral regions (59 .+-. 5 .mu.mol .cntdot. g-1 .cntdot. h-1; O2 concentration = 263 .+-. 21 .mu.M); however, the O2 concentration required for half-maximal O2 uptake was similar (.apprx. 20 .mu.M) in the two areas. The infusion of atracyloside, antimycin A, or KCN inhibited O2 uptake in both zones by 50-85%, indicating that O2 uptake in both regions was largely dependent on mitochondrial electron transport. The content of ATP and ADP and ATP:ADP were similar in microdissected samples from periportal and pericentral areas. In contrast, when livers were perfused in the retrograde direction, O2 uptake was two- to threefold greater in pericentral than in periportal regions. Maximal rates of O2 uptake correlated with the local O2 concentration irrespective of direction of flow when the electrode was moved across the liver lobule with a micromanipulator. Lower rates of O2 uptake in pericentral areas were not altered appreciably by infusion of agents known to uncouple oxidative phosphorylation (DNP), increase ADP supply (fructose), or increase in NADH redox state (ethanol or octanoate). These data are consistent with the hypothesis that maximal rates of O2 uptake are regulated, in part, in the perfused liver by O2 concentrations far above the Km of cytochrome oxidase for O2.