Pattison S E, Cousins R J
Fed Proc. 1986 Nov;45(12):2805-9.
Hepatocytes are in a dynamic equilibrium with the plasma zinc supply. Kinetic analysis of zinc uptake by isolated rat liver parenchymal cells defines two intracellular pools. In one pool zinc is bound relatively weakly and equilibrates rapidly with the medium at 37 degrees C. In the other pool zinc is bound tightly and interacts with the medium slowly at 37 degrees C. Of the two intracellular pools, the slower responding component represents an exchange process with the bulk of total cell zinc. The slow phase of uptake is saturable with albumin in the medium. The smaller pool is in rapid equilibrium with the medium and represents a labile zinc pool that accounts for net zinc accumulation. Both intracellular pools respond to hormonal stimuli. The factors that augment the uptake/exchange of zinc, namely glucocorticoids, glucagon, epinephrine, and dibutyryl cyclic AMP, are also those that stimulate metallothionein gene expression in hepatocytes. Changes in zinc flux into intracellular pools are directly related to the metallothionein content of hepatocytes. Characteristics of the labile zinc pool suggest that it may serve as an initial intermediate in zinc metabolism by hepatocytes as well as more general aspects of liver function related to zinc.
肝细胞与血浆锌供应处于动态平衡。对分离的大鼠肝脏实质细胞摄取锌的动力学分析确定了两个细胞内池。在一个池中，锌结合相对较弱，在37℃时与培养基迅速平衡。在另一个池中，锌结合紧密，在37℃时与培养基缓慢相互作用。在这两个细胞内池中，反应较慢的成分代表了与总细胞锌大部分的交换过程。摄取的慢相在培养基中可被白蛋白饱和。较小的池与培养基迅速平衡，代表一个不稳定的锌池，它负责净锌积累。两个细胞内池都对激素刺激有反应。增加锌摄取/交换的因素，即糖皮质激素、胰高血糖素、肾上腺素和二丁酰环磷腺苷，也是刺激肝细胞中金属硫蛋白基因表达的因素。锌流入细胞内池的变化与肝细胞中金属硫蛋白的含量直接相关。不稳定锌池的特征表明，它可能作为肝细胞锌代谢的初始中间体，以及与锌相关的更一般的肝功能方面。
