Role of neuregulin-1β in dexamethasone-enhanced surfactant synthesis in fetal type II cells

•Dexamethasone elevates neuregulin-1β concentration in fibroblast-conditioned media.•This effect is not the result of increased neuregulin-1β gene expression.•Surfactant phospholipid synthesis in type II cells is stimulated by neuregulin-1β.•It is concluded that neuregulin-1β is a likely component of fibroblast-pneumocyte factor. It is well established that glucocorticoids elevate the production of fibroblast-pneumocyte factor (FPF), which induces type II cells to synthesize surfactant phospholipids. FPF, however, has not been identified and it is not clear whether it is a single factor or a complex mixture of factors. In this study it has been shown that, when lung fibroblasts are exposed to dexamethasone, the concentration of neuregulin-1β (NRG1β) in conditioned medium is elevated 2-fold (P