Evidence for regulation of tyrosine hydroxylase mRNA translation by stress in rat adrenal medulla.
Evidence for regulation of tyrosine hydroxylase mRNA translation by stress in rat adrenal medulla.
复制标题
大鼠肾上腺髓质应激调节酪氨酸羟化酶 mRNA 翻译的证据。
DOI：
10.1016/j.brainres.2007.04.080
复制
发表时间：
2007
期刊：
影响因子：
2.9
通讯作者：
Tank,AWilliam
中科院分区：
文献类型：
--
作者：
Xu,Lu;Chen,Xiqun;Sun,Baoyong;Sterling,Carol;Tank,AWilliam
长期应激导致肾上腺髓质中酪氨酸羟化酶（TH）蛋白和酶活性的诱导。这种适应性反应是维持肾上腺嗜铬细胞在持续的儿茶酚胺分泌期间的儿茶酚胺生物合成能力所必需的。在这份报告中，我们证明，当大鼠受到短期应激，TH mRNA诱导至少24小时，但TH蛋白和TH活性（测定Vmax条件下）没有增加。而长期应激大鼠肾上腺TH mRNA、TH蛋白和TH活性均被诱导。使用蔗糖梯度分馏，我们表明，缺乏诱导TH蛋白后，一种类型的短期应激，一个单一的2小时固定应力与减少TH mRNA分子与多聚核糖体的百分比。相反，在重复固定后，TH mRNA的多核糖体分布与对照动物中观察到的相同，即使TH mRNA被诱导2至3倍。这些结果是一致的假设，即使TH mRNA是由短期应激诱导，控制TH mRNA翻译的机制也必须适当调节TH蛋白被诱导。
Long-term stress leads to the induction of tyrosine hydroxylase (TH) protein and enzymatic activity in the adrenal medulla. This adaptive response is necessary to maintain the catecholamine biosynthetic capacity of adrenal chromaffin cells during periods of sustained catecholamine secretion. In this report we demonstrate that when rats are subjected to short-term stress, TH mRNA is induced for at least 24 h, but TH protein and TH activity (assayed under Vmax conditions) are not increased. In contrast, adrenal TH mRNA, TH protein and TH activity are induced in rats subjected to long-term stress. Using sucrose gradient fractionation, we show that the lack of induction of TH protein after one type of short-term stressor, a single 2-h immobilization stress is associated with a decrease in the percentage of TH mRNA molecules associated with polysomes. In contrast, after repeated immobilizations the polysome profile of TH mRNA is identical to that observed in control animals, even though TH mRNA is induced 2- to 3-fold. These results are consistent with the hypothesis that even though TH mRNA is induced by short-term stressors, mechanisms that control TH mRNA translation must also be appropriately regulated for TH protein to be induced.