title: Differential changes in SP-A and disaturated phospholipids in the isolated perfused rat lung and in vivo.
abstract: Alveolar disaturated phospholipids (DSPA) increase in vivo in rats with hyperpnea and in isolated perfused lungs (IPL) in response to either salbutamol or increasing tidal volume (VT). Because surfactant protein-A (SP-A) may play a role in surfactant homeostasis, we have examined the relationship between SP-A and DSP in the alveolus lamellar bodies (LB-A), and in a vesicular (LB-B) lung subfraction. Whereas 2 h swimming increased total DSPA (approximately 48%), it had no effect on alveolar SP-A (SP-AA). In the IPL, salbutamol increased total DSPA (approximately 30%) and SP-AA (approximately 41%); increasing VT (2.5-fold) only increased DSPA (approximately 22%). SP-A and DSP also varied differentially in the tubular myelin-rich and -poor subfractions. In both the IPL and in vivo, we found inverse relationships between DSPA and SP-AA/DSPA, indicating that although SP-AA and DSPA are related, they vary independently. Whereas total SP-AA/DSPA varied between 0.046 and 0.074, it remained constant in LB-A (approximately 0.015) and LB-B (approximately 0.010), suggesting that DSP and SP-A are secreted differentially and that only a small portion of SP-AA is derived from lamellar bodies.
authors.affiliation: Department of Human Physiology, School of Medicine, Flinders University of South Australia, Adelaide, Australia.
authors.forename: I R
authors.initials: IR
authors.lastname: Doyle
authors.forename: H A
authors.initials: HA
authors.lastname: Barr
authors.forename: K G
authors.initials: KG
authors.lastname: Davidson
authors.forename: T E
authors.initials: TE
authors.lastname: Nicholas
mesh_terms: D000818:Animals; D001059:Apoproteins / Q000378:metabolism*; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism*; D008297:Male; D010477:Perfusion; D010743:Phospholipids / Q000378:metabolism*; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats
chemical_list: D001059:Apoproteins; D010743:Phospholipids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C046616:pulmonary surfactant apoprotein