Glucocorticoids modulate the in vitro development of the embryonic rat pancreas.

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Abstract
The effect of the glucocorticoid analog, dexamethasone, on the development of the embryonic pancreas was studied in tissue culture. It specifically enhanced the accumulation of exocrine enzymes without altering the level of general cell proteins. The enhancement, however, was not symmetrical: the cellular levels of the 2 major exocrine products, amylase and chymotrypsinogen, was increased about 10- and 2-fold, respectively. Two other zymogens that were present in minor quantities, procarboxypeptidases A and B, are also increased, whereas no effect was seen on lipase A. Coordinated with these effects on synthesis, there was a dramatic change in the morphology of dexamethasone-stimulated acinar cells. Their number of zymogen granules was higher and crystalline arrays are found in the rough endoplasmic reticulum. Dexamethasone also inhibited 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. Pancreatic development was normal in the absence of dexamethasone and that this glucocorticoid did not precociously induce the appearance of the specific secretory products, but rather enhances by a constant degree their synthesis and accumulation. Glucocorticoids may play a modulatory but not an inductive role in pancreatic development.