REGULATION OF (NA+ +K+)-ACTIVATED ATP HYDROLYZING ENZYME SYSTEM IN RAT KIDNEY .I. EFFECT OF ADRENALECTOMY AND SUPPLY OF SODIUM ON ENZYME SYSTEM
REGULATION OF (NA+ +K+)-ACTIVATED ATP HYDROLYZING ENZYME SYSTEM IN RAT KIDNEY .I. EFFECT OF ADRENALECTOMY AND SUPPLY OF SODIUM ON ENZYME SYSTEM
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DOI：
10.1016/0005-2744(68)90176-9
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发表时间：
1968-01-01
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影响因子：
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通讯作者：
JORGENSEN, PL
中科院分区：
文献类型：
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作者：
JORGENSEN, PL
用脱氧胆酸钠孵育正常大鼠和去肾上腺大鼠肾脏，测定(Na++K+)激活的ATP水解酶活性。经脱氧胆酸+EDTA孵育后，(Na++K+)激活的酶活力增加约3倍，而单独加入镁离子的酶活力保持不变。用这种方法可以重复性地测定(Na++K+)激活的酶的总活性。肾上腺切除后，经脱氧胆酸+EDTA处理的(Na++K+)活化酶活性降低35%~46%，而新鲜制剂的变化很小，且位于微体部分。因此，活性下降的部分原因可以归因于肾上腺切除大鼠肾脏对脱氧胆酸的反应发生了变化。肾上腺功能不全时(Na++K+)激活酶数量的减少与血浆Na、K浓度的变化速度相对应。高钠饮食可延缓并部分阻止肾上腺功能不全时(Na++K+)激活酶活性下降。这一发现表明，该酶主要不受肾上腺的控制，并可能表明Na对大鼠肾脏中(Na++K+)激活酶的活性水平有影响。
Activity of the (Na+ + K+)-activated ATP hydrolyzing enzyme was measured in the subcellular fractions from normal and adrenalectomized rat kidneys before and after incubation with sodium deoxycholate. By incubation with deoxycholate + EDTA activity of the (Na+ + K+)-activated enzyme increased about 3-fold, while the activity with Mg2+ alone remained unchanged. Using this procedure total activity of the (Na+ + K+)-activated enzyme could be measured in a reproducible way. A 35 to 46% reduction in activity of the (Na+ + K+)-activated enzyme was observed after adrenalectomy in preparations treated with deoxy-cholate + EDTA, while the changes in the fresh preparations were small and located in the microsomal fractions. Thus part of the decrease in activity could be ascribed to a change in response to deoxycholate of the enzyme in kidneys from adrenalectomized rats. The decrease in amount of the (Na+ + K+)-activated enzyme during developing adrenal insufficiency corresponded to the rate of change of plasma concentrations of Na and K. A high Na diet could postpone and partly prevent the decrease in activity of the enzyme during developing adrenal insufficiency. This finding suggests that the enzyme is not primarily under the control of the adrenals, and might indicate an effect of Na on activity levels of the (Na+ + K+)-activated enzyme in rat kidney.