Glucocorticoids stimulate elastin production in differentiated bovine ligament fibroblasts but do not induce elastin synthesis in undifferentiated cells.
Glucocorticoid treatment of fibroblasts from late gestation fetal bovine ligamentum nuchae resulted in a time- and dose-dependent selective increase in elastin production. Tropoelastin levels increased 2-3-fold in the presence of 10 nM dexamethasone while total protein synthesis and the rate of cell division decreased with glucocorticoid exposure. Two tropoelastin bands of molecular weights 64,500 and 61,000 were identified by immunoprecipitation and sodium dodecyl sulfate gradient-gel electrophoresis and both bands increased to an equal extent in the presence of dexamethasone. Undifferentiated cells from early-gestation animals did not synthesize elastin after hormone exposure, even though glucocorticoid receptors were demonstrated by nuclear-translocation experiments. These results indicate that glucocorticoids stimulate elastin production in elastin-producing ligament cells but do not induce elastin synthesis (differentiation) in undifferentiated cells.