Epstein F H, Balaban R S, Ross B D
Am J Physiol. 1982 Oct;243(4):F356-63. doi: 10.1152/ajprenal.1982.243.4.F356.
Optical spectroscopy was used to evaluate mitochondrial anoxia in the isolated perfused rat kidney by determining the percentage of cytochrome aa3 in the reduced state. Despite high levels of plasma flow (greater than 20 ml . g-1 . min-1) and venous PO2 (greater than 300 mmHg), 25--40% of cytochrome aa3 appeared to be in its reduced form. Agents that alter metabolism or transport primarily in renal cortex had little or no effect on the redox state of cytochrome aa3. These included 3-mercaptopicolinate, an inhibitor of gluconeogenesis; 2-tetradecylglycidic acid, an inhibitor of fat metabolism via carnitine-fatty acyltransferase, and acetazolamide. In contrast, a decrease in medullary transport induced by the loop diuretics bumetanide or furosemide produced an increase in cytochrome aa3 oxidation consistent with a decrease in transport-related oxygen consumption in the hypoxic area. The results suggest that substantial portions of the kidney, particularly in the renal medulla, may normally operate on the brink of anoxia despite high PO2 in artery and vein.
通过测定还原状态下细胞色素aa3的百分比，利用光学光谱法评估离体灌注大鼠肾脏中的线粒体缺氧情况。尽管血浆流量较高（大于20 ml·g-1·min-1）且静脉血氧分压较高（大于300 mmHg），但仍有25% - 40%的细胞色素aa3似乎处于还原形式。主要改变肾皮质代谢或转运的药物对细胞色素aa3的氧化还原状态几乎没有影响。这些药物包括糖异生抑制剂3 - 巯基吡啶甲酸盐、通过肉碱 - 脂肪酰基转移酶抑制脂肪代谢的2 - 十四烷基缩水甘油酸以及乙酰唑胺。相比之下，髓袢利尿剂布美他尼或呋塞米引起的髓质转运减少导致细胞色素aa3氧化增加，这与缺氧区域与转运相关的氧消耗减少一致。结果表明，尽管动脉和静脉中的血氧分压较高，但肾脏的大部分区域，特别是肾髓质，可能通常处于缺氧边缘运行。
