Incorporation of (3H) palmitate into disaturated phosphatidylcholines in alveolar type II cells isolated by centrifugal elutriation.
Miles-PR; Wright-JR; Bowman-L; Castranova-V
Biochim Biophys Acta 1983; 753:107-118
The incorporation of tritium labelled palmitate in the surfactant synthesis of disaturated phosphatidylcholines (PC) was studied in alveolar type-II cells isolated from rats. The cells were isolated by elastase digestion from the lungs of male Sprague-Dawley-rats and then purified by centrifugal elutriation. The rate of incorporation of palmitate into disaturated PC was measured in 420,000 cells suspended in a phosphate buffered medium containing 1.8 millimoles (mmol) calcium-chloride (7646799) and 1.0mmol magnesium-chloride (7786303). Initial amounts of palmitate ranged from approximately of magnesium (Mg+2) and calcium (Ca+2) ions on the reaction were studied by varying the ion concentration medium containing 420,000 cells and 0.1mmol palmitate, 0.5ml volume. Pulmonary lavage fluid was added to 0.5ml of the medium, 420,000 cells and 0.1mmol palmitate, to study its effect on the reaction. The rate was found to be directly proportional to the palmitate concentration and the maximum rate occurred 4 to 5 hours after initiation of the reaction. Ca+2 ions had an inhibitory effect on the reaction whereas Mg+2 ions showed a small catalytic effect. When both ions were present, the rate of incorporation was the same as when the ions were absent. Pulmonary lavage fluid was found to inhibit the reaction rate. The authors conclude that some as yet unidentified components in pulmonary fluid inhibit PC synthesis.
NIOSH-Author; Animal-studies; Biochemical-tests; Biological-effects; Enzyme-activity; Chemical-properties; Quantitative-analysis; Biological-factors; Laboratory-testing; Cell-cultures
Biochimica et Biophysica Acta