Direct effects of corticotropin-releasing hormone and thyrotropin-releasing hormone on fetal lung explants

Fetal lung produces corticotropin-releasing hormone (CRH) without known dir ect effects. We tested the hypothesis that CRH can directly regulate lung development. In baboon fetal lung explants, CRH strongly induces surfactant phospholipid synthesis and SP-C immunostaining, plus [H-3]thymidine incorp oration. CRH receptor mRNA was detected in lung from multiple baboons at e1 25. Testing thyrotropin (TRH) as a specificity control, we did demonstrate different direct effects with only modest stimulation of surfactant phospho lipid synthesis and strong induction of cytidylyltransferase gene expressio n. Therefore, CRH, similar to ACTH and glucocorticoids, is a potent inducer of cell differentiation in fetal lung. (C) 2000 Published by Elsevier Scie nce Inc.