Doucet A, Hus-Citharel A, Morel F
Am J Physiol. 1986 Nov;251(5 Pt 2):F851-7. doi: 10.1152/ajprenal.1986.251.5.F851.
Dexamethasone has been reported to stimulate Na-K-ATPase activity in the medullary thick ascending limb of adrenalectomized animals within a few hours. The present study was aimed at characterizing the mechanism of this action by investigating the stimulatory effect of the hormone in vitro. Dexamethasone (10(-8) M) added in vitro to segments of the medullary thick ascending limb of Henle's loop, which were microdissected from adrenalectomized rats, restored in a dose-dependent manner the depressed Na-K-ATPase activity within one h of incubation. This stimulation of Na-K-ATPase was inhibited by cycloheximide and actinomycin D. Dexamethasone also stimulated the component of oxidative metabolism coupled to sodium transport. These results, which confirm previous in vivo observations, demonstrate that dexamethasone-induced stimulation of Na-K-ATPase is a direct tubular action of the hormone mediated by protein synthesis. They suggest that this short-term effect of dexamethasone corresponds to the stimulation of sodium reabsorption by the dilution segment.
据报道，地塞米松能在数小时内刺激去肾上腺动物髓袢升支粗段的钠钾ATP酶活性。本研究旨在通过体外研究该激素的刺激作用来阐明其作用机制。将地塞米松（10^(-8) M）体外添加到从去肾上腺大鼠显微解剖得到的髓袢升支粗段片段中，孵育1小时内，以剂量依赖方式恢复了降低的钠钾ATP酶活性。钠钾ATP酶的这种刺激作用被环己酰亚胺和放线菌素D抑制。地塞米松还刺激了与钠转运偶联的氧化代谢成分。这些结果证实了先前的体内观察结果，表明地塞米松诱导的钠钾ATP酶刺激是该激素通过蛋白质合成介导的直接肾小管作用。它们表明地塞米松的这种短期作用对应于稀释段对钠重吸收的刺激。
