Effect of CO2 concentration on phosphatidylcholine and phosphatidylglycerol metabolism in surfactant and residual lung fractions.
An investigation of the effect of change of total CO(2) concentration from 7 to 43 mM at pH 7.35 in the medium perfusing isolated rat lungs on [U-(14)C]glucose incorporation into lung phospholipids has been carried out. The incorporation of [U-(14)C]glucose into phosphatidylcholine and phosphatidylglycerol of the surfactant fraction and of the remaining lung tissue (residual fraction) was observed. Increased CO(2) concentration increased [U-(14)C]glucose incorporation into phosphatidylcholine of the surfactant fraction and residual fraction by 43 and 50%, respectively, during a 2 hr perfusion. Likewise, incorporation of [U-(14)C]glucose into phosphatidylglycerol was increased 22 and 34% into the surfactant and residual fractions, respectively. The percentage of [U-(14)C]glucose incorporated into the fatty acid moieties of phosphatidylcholine of both fractions increased as a result of increased CO(2) concentration. The increase in the incorporation of [U-(14)C]glucose into the fatty acid moieties of phosphatidylcholine was confirmed by an average increase of 56 and 77% in the specific activity of palmitic acid isolated from phosphatidylcholine of the surfactant and residual fraction, respectively, as a result of increased CO(2) concentration. The results suggest that alteration in extracellular CO(2) concentration affects the de novo synthesis from glucose of phosphatidylcholine and phosphatidylglycerol of the surfactant-lipoprotein fraction of lung.
D000818:Animals; D002245:Carbon Dioxide / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010169:Palmitic Acids / Q000096:biosynthesis; D010477:Perfusion; D010713:Phosphatidylcholines / Q000378:metabolism*; D010715:Phosphatidylglycerols / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats
D010169:Palmitic Acids; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants; D002245:Carbon Dioxide; D005947:Glucose