Differential changes in surfactant protein-a (sp-a) and disaturated
phospholipids in the isolated perfused rat lung and in vivo.
Doyle, Ian R, Heather A Barr, Kate G Davidson, Terence E Nicholas.
Department of Human Physiology, School of Medicine, Flinders
University of South Australia, Adelaide, Australia
APStracts 3:0074L, 1996.
Alveolar (A) disaturated phospholipids (DSP) increase in rats in vivo
with hyperpnea, and in isolated perfused lungs (IPL) in response to
either salbutamol or increasing VT. Since 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 a vesicular (Lb-B) lung subfraction. Whereas 2 h swimming
increased total DSPA (48%), it had no effect on SP-AA. In the IPL,
salbutamol increased total DSPA (30%) and SP-AA (41%); increasing VT
(2.5-fold) only increased DSPA (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 (0.015) and Lb-B
(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.
Received 10 November 1995; accepted in final form 24 April 1996.
APS Manuscript Number L323-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 May 96