Abstract
Beta-adrenergic agonists enhance surfactant release, presumably by increasing synthesis of cAMP and activation of cAMP-dependent protein kinase. The present study compares the effect of terbutaline and forskolin on cAMP levels, protein kinase activation ratios, and surfactant release in isolated rat lung Type II epithelial cells in primary culture. Cytosolic cAMP levels rose significantly by 1 minute following exposure and persisted past 20 minutes:
p<.05 by analysis of variance for all groups compared to control; mean±SEM of three experiments; fmols/100 ul.
T plus F had a synergistic effect on cAMP levels. Protein kinase activation ratio increased in the presence of T+F from .45±.03 for C to 0.85±.05 for T+F. The effect of T and F on surfactant release was additive:C=0±21%, T=187±8%, F=258±45%, T+F=412±74% (mean±SEM). Dose response curves resulted in EC50 values of 1 uM and 0.5 uM for T and F, respectively. Our results demonstrate a rise in cytosolic cAMP levels, increased protein kinase activation ratios, and subsequent surfactant release from isolated Type II cells, supporting a role for cAMP as a second messenger for stimulated surfactant release.
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Rice, W., Hull, W. & Whitsett, J. ROLE OF CYCLIC 3′,5′-ADENOSINE MONOPHOSPHATE (cAMP) IN SURFACTANT RELEASE FROM TYPE II EPITHELIAL CELLS. Pediatr Res 18 (Suppl 4), 159 (1984). https://doi.org/10.1203/00006450-198404001-00399
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DOI: https://doi.org/10.1203/00006450-198404001-00399