Zeytin F N, Rusk S F
Laboratory for Neuroendocrinology, Salk Institute, La Jolla, California 92037.
Endocrinology. 1988 Mar;122(3):1129-32. doi: 10.1210/endo-122-3-1129.
A clonal multipeptide-secreting cell line (44-2C) was used to study the interaction of basic fibroblast growth factor (bFGF) and GRF. The experiments were carried out in cells maintained under serum-free conditions in the absence of growth factors and hormonal supplements. We have shown that in 44-2C cells, rat hypothalamic GRF (rGRF) stimulates neurotensin, calcitonin, and somatostatin secretion. bFGF is not a mitogen in the 44-2C cells, but does regulate differentiated function by a mechanism involving regulation of RNA stabilization. The results presented here show for the first time that FGF acts as a competence factor mediating the cellular action of rGRF. In FGF-pretreated cells, 4-h exposure to rGRF stimulated RNA and protein synthesis. In this cell line rGRF was biologically active at 10(-14) M, and the ED50 for rGRF-mediated RNA and protein synthesis ranged from 10(-11) to 10(-12) M. We conclude that the interaction of FGF, acting as a permissive factor, and rGRF results in a novel mechanism of action for rGRF. These findings suggest that hypophysiotropic factors affect the cellular milieu in concert with growth factors, such as bFGF.
使用一种克隆的多肽分泌细胞系（44-2C）来研究碱性成纤维细胞生长因子（bFGF）与生长激素释放因子（GRF）之间的相互作用。实验在无血清条件下、无生长因子和激素补充剂的细胞中进行。我们已经表明，在44-2C细胞中，大鼠下丘脑GRF（rGRF）刺激神经降压素、降钙素和生长抑素的分泌。bFGF在44-2C细胞中不是促有丝分裂原，但确实通过一种涉及RNA稳定性调节的机制来调节分化功能。此处呈现的结果首次表明，FGF作为一种感受态因子介导rGRF的细胞作用。在FGF预处理的细胞中，4小时暴露于rGRF可刺激RNA和蛋白质合成。在该细胞系中，rGRF在10^(-14) M时具有生物活性，rGRF介导的RNA和蛋白质合成的半数有效剂量（ED50）范围为10^(-11)至10^(-12) M。我们得出结论，作为一种许可因子的FGF与rGRF的相互作用导致了rGRF一种新的作用机制。这些发现表明，促垂体激素因子与生长因子（如bFGF）协同影响细胞环境。
