Rall L, Pictet R, Githens S, Rutter W J
J Cell Biol. 1977 Nov;75(2 Pt 1):398-409. doi: 10.1083/jcb.75.2.398.
The effect of the glucocorticoid analogue, dexamethasone, on the development of the embryonic pancreas was studied in tissue culture. It specifically enhances the accumulation of exocrine enzymes without altering the level of general cell proteins. The enhancement, however, is not symmetrical: the cellular levels of the two major exocrine products, amylase and chymotrypsinogen, are increased about 10- and 2-fold, respectively. Two other zymogens that are present in minor quantities, procarboxypeptidases A and B, are also increased, whereas no effect is seen on lipase A. Coordinate with these effects on synthesis, there is a dramatic change in the morphology of dexamethasone-stimulated acinar cells. Their number of zymogen granules is higher and crystalline arrays are found in the rough endoplasmic reticulum. Dexamethasone also inhibits cell replication, perhaps by selectively inhibiting the last cell divisions of the culture period. At the same time, there is a disproportionate reduction in the insulin content of cultured rudiments. We find that pancreatic development is normal in the absence of dexamethasone and that this glucocorticoid does not precociously induce the appearance of the specific secretory products, but rather enhances by a constant degree their synthesis and accumulation. Therefore, we conclude that glucocorticoids may play a modulatory but not an inductive role in pancreatic development.
在组织培养中研究了糖皮质激素类似物地塞米松对胚胎胰腺发育的影响。它能特异性增强外分泌酶的积累，而不改变一般细胞蛋白质的水平。然而，这种增强并不对称：两种主要外分泌产物淀粉酶和胰凝乳蛋白酶原的细胞水平分别增加了约10倍和2倍。另外两种少量存在的酶原，羧肽酶原A和B也增加了，而对脂肪酶A则没有影响。与这些对合成的影响相一致，地塞米松刺激的腺泡细胞形态发生了显著变化。它们的酶原颗粒数量更多，并且在粗面内质网中发现了晶体阵列。地塞米松还抑制细胞复制，可能是通过选择性抑制培养期的最后细胞分裂。与此同时，培养的胰腺原基中的胰岛素含量不成比例地减少。我们发现，在没有地塞米松的情况下胰腺发育正常，并且这种糖皮质激素不会过早诱导特定分泌产物的出现，而是以恒定程度增强它们的合成和积累。因此，我们得出结论，糖皮质激素在胰腺发育中可能起调节作用而非诱导作用。
