Formation of lung surfactant films from intact lamellar bodies.

AUTOR(ES)

Paul, G W

RESUMO

Lamellar bodies, an intracellular source of lung alveolar surfactant, were isolated from rat lung homogenates and studied in the Langmuir-Adams surface balance. By layering intact lamellar bodies on the surface of a more dense sucrose subphase, we studied the factors affecting film formation from surface tension-vs-time data and determined surface tension-surface area isotherms by compression and expansion of the resulting films. We found that films with properties representative of the alveolar surfactant are formed in the presence of Ca2+ or Mg2+ alone, or either plus Na+; that film formation is incomplete with Na+ alone or on ion-free subphases; and that Ca2+-induced film formation is blocked by chelation with EGTA but is unaffected by diisopropylfluorophosphate. The results suggest that divalent cations induce film formation by interactions at sites within the lamellar bodies and may be responsible for the binding of membrane lipids to membrane proteins in lung surfactant.

Documentos Relacionados

• Isolation and characterization of two hydroxyproline-containing glycoproteins from normal animal lung lavage and lamellar bodies.
• Analysis of Labeling and Clearance of Lung Surfactant Phospholipids in Rabbit: EVIDENCE OF BIDIRECTIONAL SURFACTANT FLUX BETWEEN LAMELLAR BODIES AND ALVEOLAR LAVAGE
• Uptake of lectins by pulmonary alveolar type II cells: subsequent deposition into lamellar bodies.
• Ascorbic acid prevents oxidative stress in glutathione-deficient mice: effects on lung type 2 cell lamellar bodies, lung surfactant, and skeletal muscle.
• Ultrasonography of foreign bodies.