Bonewitz R F, Foulkes E C, O'Flaherty E J, Hertzberg V
Dev Toxicol Environ Sci. 1982;9:203-14.
Several studies have linked hepatic metallothionein (MT) synthesis to changes in zinc metabolism in response to various forms of stress and to administration of glucocorticoid hormones. There is also some evidence that the intestinal absorption of Zn is enhanced under such conditions. The present studies were designed to investigate the effect of dexamethasone on the kinetics of Zn uptake in an isolated segment of the adult rat jejunum, perfused through the lumen and maintained in situ. Dexamethasone administered to adrenalectomized rats was found to affect significantly one of the parameters of the equation describing 65Zn uptake. Because the observed effect was kinetically consistent with an increased synthesis of MT in the jejunal mucosa, the synthesis of MT was monitored with 35S-cystine in both the liver and intestine of adrenalectomized rats given dexamethasone. Under these conditions, MT synthesis was significantly increased in the liver but not in the jejunal mucosa. The results indicate that dexamethasone is able to alter the kinetics of Zn uptake in the jejunum, but does so without increased jejunal MT synthesis.
多项研究已将肝脏金属硫蛋白（MT）的合成与应对各种形式应激以及给予糖皮质激素时锌代谢的变化联系起来。也有一些证据表明，在这种情况下锌的肠道吸收会增强。本研究旨在探讨地塞米松对成年大鼠空肠分离段锌摄取动力学的影响，该空肠段通过肠腔灌注并原位维持。结果发现，给肾上腺切除的大鼠注射地塞米松会显著影响描述65Zn摄取的方程中的一个参数。由于观察到的效应在动力学上与空肠黏膜中MT合成增加一致，因此在给予地塞米松的肾上腺切除大鼠的肝脏和肠道中用35S-胱氨酸监测MT的合成。在这些条件下，肝脏中MT合成显著增加，但空肠黏膜中未增加。结果表明，地塞米松能够改变空肠中锌摄取的动力学，但这样做时空肠MT合成并未增加。
