Two‐Dimensional gel electrophoresis of dexamethasoneinduced organ‐specific developmental proteins (fsa,fsb) in rat lung fibroblasts

Glucocorticoids are known to enhance fetal lung maturation. Previous studies with whole lung have shown that specific proteins are enhanced by these hormones. At least two effects of glucocorticoids on fetal lung epithelia require the presence of mesenchymal elements. Since the lung consists of several different cell types, further understanding of glucocorticoid effects on fetal lung protein synthesis requires that such studies be carried out with specific cell types. Using two‐dimensional gel electrophoresis, we have examined the synthesis and secretion of proteins by fetal rat lung fibroblasts in the presence and absence of glucocorticoid. Two proteins, fsa and fsb, are enhanced by dexamethasone, appear to be organ specific, and are enhanced only during prenatal and early postnatal life. They are not enhanced by a variety of other hormones.