Olson M J, Thurman R G
Arch Biochem Biophys. 1987 Feb 15;253(1):26-37. doi: 10.1016/0003-9861(87)90633-3.
A method has been devised to quantitate rates of ketogenesis (acetoacetate + beta-hydroxybutyrate production) in discrete regions of the liver lobule based on changes in NADH fluorescence. In perfused livers from fasted rats, ketogenesis was inhibited nearly completely with either 2-bromoctanoate (600 microM) or 2-tetradecylglycidic acid (25 microM). During inhibition of ketogenesis, a linear relationship (r = 0.90) was observed between decreases in NADH fluorescence detected from the liver surface and decreases in ketone body production. NADH fluorescence was monitored subsequently from individual regions of the liver lobule by placing microlight guides on periportal and pericentral regions of the liver lobule visible on the liver surface. Rates of ketogenesis in sublobular regions were calculated from regional decreases in NADH fluorescence and changes in the rate of ketone body formation by the whole liver during infusion of inhibitors. In the presence of bromoctanoate, ketogenesis was reduced 80% and local rates of ketogenesis were decreased 31 +/- 4 mumol/g/h in periportal areas and 28 +/- 3 mumol/g/h in pericentral regions. Similar results were observed with tetradecylglycidic acid. Therefore, it was concluded that submaximal rates of ketogenesis from endogenous, mainly long-chain fatty acids are nearly equal in periportal and pericentral regions of the liver lobule in liver from fasted rats. Rates of ketogenesis and NADH fluorescence were strongly correlated during fatty acid infusion. Infusion of 250 microM oleate increased NADH fluorescence maximally by 8 +/- 1% over basal values in periportal regions and 17 +/- 4% in pericentral areas. Local rates of ketogenesis, calculated from these changes in fluorescence, increased 35 +/- 6 mumol/g/h in periportal areas and 55 +/- 5 mumol/g/h in pericentral regions. Thus, oleate stimulated ketogenesis nearly 60% more in pericentral than in periportal regions of the liver lobule.
已设计出一种基于NADH荧光变化来定量肝小叶离散区域酮生成速率（乙酰乙酸 + β-羟基丁酸生成速率）的方法。在禁食大鼠的灌注肝脏中，用2-溴辛酸（600微摩尔）或2-十四烷基缩水甘油酸（25微摩尔）几乎可完全抑制酮生成。在抑制酮生成过程中，从肝脏表面检测到的NADH荧光降低与酮体生成减少之间呈现线性关系（r = 0.90）。随后，通过将微光导放置在肝脏表面可见的肝小叶门周和中央周围区域，监测肝小叶各个区域的NADH荧光。小叶下区域的酮生成速率根据NADH荧光的区域降低以及抑制剂输注期间全肝酮体形成速率的变化来计算。在存在溴辛酸的情况下，酮生成减少80%，门周区域的局部酮生成速率降低31±4微摩尔/克/小时，中央周围区域降低28±3微摩尔/克/小时。用十四烷基缩水甘油酸观察到类似结果。因此，得出结论：禁食大鼠肝脏肝小叶的门周和中央周围区域中，以内源性、主要是长链脂肪酸为底物的亚最大酮生成速率几乎相等。脂肪酸输注期间，酮生成速率与NADH荧光密切相关。输注250微摩尔油酸使门周区域的NADH荧光最大比基础值增加8±1%，中央周围区域增加17±4%。根据这些荧光变化计算的局部酮生成速率，门周区域增加35±6微摩尔/克/小时，中央周围区域增加55±5微摩尔/克/小时。因此，油酸刺激肝小叶中央周围区域的酮生成比门周区域多近60%。
