脑微粒体钠钾激活的三磷酸腺苷酶：二苯乙内酰脲对钠抑制作用的修饰

Sodium-potassium-activated adenosine triphosphatase of brain microsomes: modification of sodium inhibition by diphenylhydantoins.

作者信息

Siegel G J, Goodwin B B

出版信息

J Clin Invest. 1972 May;51(5):1164-9. doi: 10.1172/JCI106909.

DOI:10.1172/JCI106909

PMID:4259828

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC292246/

Abstract

Effects of diphenylhydantoins on (Na(+) + K(+))-ATPase activity in rat and cat brain microsomes were studied. 5,5-diphenylhydantoin (DPH) in concentrations of 5-20 mug ml(-1) produces an apparent stimulation of the rat brain (Na(+) + K(+))-activated ATPase of 55-65% in media containing 50 mM Na(+), 0.15 mM K(+), 3 mM Mg(++), and 3 mM ATP. No effects are found on the Mg-ATPase. At constant K(+) levels of 0.05 mmole/liter and 0.15 mmole/liter, increasing the Na(+) concentration activates the enzyme similarly with and without DPH. However, Na(+) concentrations greater than 5 mmoles/liter and 10 mmoles/liter, respectively, which are inhibitory in these low K(+) media, produce less inhibition in the presence of DPH. In media containing 10 mM Na(+), the K(+) activation, on the other hand, is potentiated by DPH. In preparations from cat brain qualitatively similar results are obtained. No effect of DPH is seen on the inhibition produced by high K(+) in low Na(+) media. DPH produces an approximately constant apparent stimulation of 45% in the (Na(+) + K(+)) increments when these ions are varied simultaneously at a fixed ratio of 150 Na(+):1 K(+) with cat brain extracts. 5-(p-hydroxyphenyl)-5-phenylhydantoin (HPPH) has the same potency as DPH in reducing the Na(+) inhibition at high Na:K ratios. The hydantoins appear to act by decreasing the Na(+) inhibition that occurs at high Na:K ratios.

摘要

研究了二苯乙内酰脲对大鼠和猫脑微粒体中（Na⁺ + K⁺）-ATP酶活性的影响。在含有50 mM Na⁺、0.15 mM K⁺、3 mM Mg²⁺和3 mM ATP的介质中，浓度为5 - 20 μg/ml的5,5-二苯乙内酰脲（DPH）能使大鼠脑（Na⁺ + K⁺）激活的ATP酶明显刺激55% - 65%。对Mg-ATP酶无影响。在K⁺水平恒定为0.05 mmol/L和0.15 mmol/L时，增加Na⁺浓度，无论有无DPH，酶的激活情况相似。然而，在这些低钾介质中分别大于5 mmol/L和10 mmol/L的Na⁺浓度具有抑制作用，在有DPH存在时抑制作用较小。在含有10 mM Na⁺的介质中，另一方面，DPH增强了K⁺的激活作用。从猫脑制备物中获得了定性相似的结果。在低Na⁺介质中高K⁺产生的抑制作用方面，未观察到DPH有影响。当以150 Na⁺:1 K⁺的固定比例同时改变这些离子时，DPH在猫脑提取物中（Na⁺ + K⁺）增加时产生约45%的近似恒定明显刺激。5-（对羟基苯基）-5-苯基乙内酰脲（HPPH）在高Na:K比时降低Na⁺抑制作用方面与DPH具有相同效力。乙内酰脲类似乎通过减少高Na:K比时发生的Na⁺抑制作用来发挥作用。