Tushinski R J, Sussman P M, Yu L Y, Bancroft F C
Proc Natl Acad Sci U S A. 1977 Jun;74(6):2357-61. doi: 10.1073/pnas.74.6.2357.
We have investigated whether the large (5- to 15-fold) stimulation of synthesis of growth hormone (somatotropin) observed upon exposure of a strain of rat pituitary (GH3) cells to dexamethasone (a synthetic glucocorticoid) arises from a stimulation of pregrowth hormone mRNA. A good agreement was observed between the stimulation of growth hormone synthesis and the stimulation of cytoplasmic levels of pregrowth hormone mRNA, assayed by translation in wheat germ extracts. Electrophoresis on formamide-acrylamide gels of oligo(dT)-treated membrane fraction RNA revealed a band that was induced by dexamethasone to about the same extent as was translatable pregrowth hormone mRNA. Elution of the band and translation in wheat germ extracts showed directly that it contained pregrowth hormone mRNA. These results suggest that the dexamethasone induction of growth hormone synthesis in GH3 cells arises from an accumulation of pregrowth hormone mRNA in the cytoplasm of the cells. The pregrowth hormone mRNA band observed by gel electrophoresis had an estimated molecular weight of 3.6 X 10(5), suggesting the existence in this molecule of an untranslated region at least 200 nucleotides in length.
我们研究了将大鼠垂体（GH3）细胞株暴露于地塞米松（一种合成糖皮质激素）时观察到的生长激素（促生长素）合成的大幅（5至15倍）刺激是否源于前生长激素mRNA的刺激。通过在小麦胚芽提取物中进行翻译测定，观察到生长激素合成的刺激与前生长激素mRNA细胞质水平的刺激之间具有良好的一致性。对经寡聚（dT）处理的膜部分RNA进行甲酰胺 - 丙烯酰胺凝胶电泳，显示出一条带，其被地塞米松诱导的程度与可翻译的前生长激素mRNA大致相同。洗脱该条带并在小麦胚芽提取物中进行翻译直接表明它含有前生长激素mRNA。这些结果表明，地塞米松诱导GH3细胞中生长激素的合成源于前生长激素mRNA在细胞细胞质中的积累。通过凝胶电泳观察到的前生长激素mRNA条带的估计分子量为3.6×10⁵，表明该分子中存在长度至少为200个核苷酸的非翻译区。
