期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1977
卷号:74
期号:6
页码:2357-2361
DOI:10.1073/pnas.74.6.2357
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要: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.