Developmental regulation of Na, K-ATPase in rat lung

Late in gestation lung epithelium changes from net chloride and fluid secretion to sodium and fluid absorption. Fluid resorption is required for postnatal gas exchange and occurs by combined action of epithelial sodium channels and Na, K-ATPase. We hypothesized that alveolar epithelial Na, K-ATPase...

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Published inThe American journal of physiology Vol. 270; no. 4 Pt 1; p. L619
Main Authors Ingbar, D H, Weeks, C B, Gilmore-Hebert, M, Jacobsen, E, Duvick, S, Dowin, R, Savik, S K, Jamieson, J D
Format Journal Article
LanguageEnglish
Published United States 01.04.1996
Subjects
Aging - metabolism
Animals
Animals, Newborn
Blotting, Northern
Blotting, Western
Embryo, Mammalian - metabolism
Embryonic and Fetal Development
Fluorescent Antibody Technique, Indirect
Gene Expression
Immunohistochemistry
Lung - embryology
Lung - enzymology
Lung - growth & development
Rats
Rats, Sprague-Dawley
Sodium-Potassium-Exchanging ATPase - genetics
Sodium-Potassium-Exchanging ATPase - metabolism
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Summary:Late in gestation lung epithelium changes from net chloride and fluid secretion to sodium and fluid absorption. Fluid resorption is required for postnatal gas exchange and occurs by combined action of epithelial sodium channels and Na, K-ATPase. We hypothesized that alveolar epithelial Na, K-ATPase increases perinatally. Immunofluorescence (IF) and immunoelectron microscopy (IEM) with a monoclonal anti-alpha subunit antibody demonstrated that Na, K-ATPase was present on the basolateral surfaces of columnar epithelial cells at fetal day (FD) 17 and on type II cells throughout development. However, type I epithelial cells did not have detectable Na,K-ATPase. The steady-state levels of both the alpha 1 isoform and the beta-subunit mRNAs were maximal at FD20-neonatal day (ND) 1, with consistent increases from FD17 level. Na, K-ATPase alpha-subunit protein also increased from FD17 to FD20-22 and then decreased in the early postnatal period. The ouabain-inhibitable sodium pump activity per milligram membrane protein increased 2.6-fold from FD17 to FD22-ND1 (P < 0.05). The quantities of sodium pump mRNA, antigenic protein, and enzyme activity increase in late gestation in accord with a proposed role for Na, K-ATPase in resorption of alveolar sodium and fluid in preparation for birth.
ISSN:0002-9513
DOI:10.1152/ajplung.1996.270.4.l619