Jung K Y, Endou H
Department of Pharmacology, Faculty of Medicine, University of Tokyo, Japan.
Ren Physiol Biochem. 1990 Sep-Oct;13(5):248-58. doi: 10.1159/000173366.
To characterize the properties of cellular adenosine triphosphate (ATP) production and consumption in the descending thin limb of Henle's loop (DTL) in rats, we measured the cellular ATP content by applying the microchemiluminescence method. For ATP production, isolated DTL from the short- and long-loop nephron (SDL and LDL, respectively) was incubated with several substrates such as alanine, glucose, glutamine, beta-hydroxybutyrate (beta-HBA), lactate, and pyruvate; for ATP production from each substrate indicated that glucose and pyruvate were the preferred substrates to maintain cellular ATP in both SDL and LDL. ATP production from glutamine, beta-HBA, and lactate was substantial in LDL. In SDL, glutamine was the preferred substrate, and beta-HBA and lactate were minimal. The utilization of alanine was minimal in both LDL and SDL. The cellular ATP was significantly restored by ouabain at concentrations of 1.5 x 10(-5) and 1.5 x 10(-3) M in LDL, but in SDL only at 1.5 x 10(-3) M. In both segments, the cellular ATP level was significantly decreased by monensin above the concentrations of 1 micrograms/ml in LDL and 5 micrograms/ml in SDL. From these observations, we conclude that there exist clear differences between LDL and SDL in ATP-supplying substrate specificities and ATP-consuming properties.
为了描述大鼠髓袢降支细段（DTL）中细胞三磷酸腺苷（ATP）产生和消耗的特性，我们应用微化学发光法测量了细胞ATP含量。对于ATP的产生，分别从短袢和长袢肾单位分离出的DTL（分别为SDL和LDL）与几种底物一起孵育，如丙氨酸、葡萄糖、谷氨酰胺、β-羟基丁酸（β-HBA）、乳酸和丙酮酸；对每种底物产生ATP的情况表明，葡萄糖和丙酮酸是维持SDL和LDL中细胞ATP的首选底物。在LDL中，谷氨酰胺、β-HBA和乳酸产生的ATP相当可观。在SDL中，谷氨酰胺是首选底物，而β-HBA和乳酸产生的ATP极少。在LDL和SDL中，丙氨酸的利用都极少。在LDL中，哇巴因在浓度为1.5×10⁻⁵和1.5×10⁻³ M时能显著恢复细胞ATP，但在SDL中仅在1.5×10⁻³ M时有效。在两个节段中，当莫能菌素在LDL中的浓度高于1微克/毫升、在SDL中的浓度高于5微克/毫升时，细胞ATP水平会显著降低。从这些观察结果中，我们得出结论，LDL和SDL在ATP供应底物特异性和ATP消耗特性方面存在明显差异。
