Metabolism of Isolated Kidney Tubules
Metabolism of Isolated Kidney Tubules
复制标题
离体肾小管的代谢
DOI：
10.1111/j.1432-1033.1972.tb02502.x
复制
发表时间：
1972
期刊：
影响因子：
5.4
通讯作者：
B. Stukowski
中科院分区：
文献类型：
--
作者：
W. Guder;O. Wieland;B. Stukowski
Pyruvate dehydrogenase activity was measured in extracts of isolated kidney cortex tubules, prepared by collagenase treatment. The measured activities were comparable to those described previously for whole kidney homogenates.
Incubation of tubules in vitro in the absence of exogenous substrates led to a steady increase in enzyme activity over 30 min. This increase was not significantly changed by the addition of several gluconeogenic substrates including lactate, glutamine, glutamate, glycerol, fructose and malate. 1 mM oleate, 5 mM acetate and 20 mM 2-oxoglutarate however, prevented this increase completely. In contrast, glucose and dihydroxyacetone accelerated the activation of pyruvate dehydrogenase during incubation in vitro. 20 mM pyruvate very rapidly activated pyruvate dehydrogenase with a following decrease below the activity of control experiments without substrate. 1 mM oleate and 20 mM 2-oxoglutarate counteracted the increase in pyruvate dehydrogenase activity caused by glucose and dihydroxyacetone and had no effect in the presence of 20 mM pyruvate.
Determination of the inactive part of pyruvate dehydrogenase after addition of purified pyruvate dehydrogenase phosphatase revealed that all changes observed were probably caused by enzymatic interconversion of pyruvate dehydrogenase.
The results are compared with previously published observations on the regulation of pyruvate dehydrogenase in vivo and confirm the role of fatty acids in the regulation of kidney cortex pyruvate metabolism.
