title: Modulation of sodium transport in alveolar epithelial cells by estradiol and progesterone.
abstract: The effects of estradiol (E2) and progesterone (P) on alveolar epithelial Na+ transport were studied in isolated alveolar epithelial cells from 18- to 19-d GA rat fetuses, grown to confluence in serum-free media supplemented with E2 (0-1 μM) and P (0-2.8 μM). Short-circuit currents (ISC) were measured, showing an increase by E2 and P in a dose-dependent manner. The Na,K-ATPase subunits -α1 and -β1 were detected by Western blotting, but total expression was not significantly altered. Furthermore, all three epithelial Na+ channel (ENaC) subunits -α, -β, and -γ were detected, with trends toward a higher expression in the presence of E2 and P. Real-time PCR revealed an increase of α- and β-ENaC expression but no alteration of γ-ENaC. In addition, the mRNA expression of cystic fibrosis transmembrane conductance regulator (CFTR) and Na,K-ATPase-β1 subunit were elevated in the presence of E2 and P. Single-channel patch clamp analysis demonstrated putative highly selective and nonselective cation channels in the analyzed cells, with a higher percentage of responsive patches under the influence of E2 and P. We conclude that E2 and P increased Na+ transport in alveolar epithelial cells by enhancing the expression and activity of ENaC and Na,K-ATPase.
authors.affiliation: Department of Neonatology, University of Leipzig, Leipzig 04103, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Laube
authors.forename: Eva
authors.initials: E
authors.lastname: Küppers
authors.forename: Ulrich H
authors.initials: UH
authors.lastname: Thome
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004594:Electrophysiology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D011374:Progesterone / Q000494:pharmacology*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*
chemical_list: D011374:Progesterone; D004958:Estradiol; D012964:Sodium