Oxygen modulates surfactant protein mrna expression and phospholipid production in human fetal lung in vitro. Acarregui, Michael J., Jennifer J. Brown, and Rama Mallampalli. Departments of Pediatrics and Internal Medicine, University of Iowa College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242
APStracts 2:0015L, 1995.
We studied the effect of 20% to 95% oxygen upon mRNA levels for the surfactant-associated proteins, SP-A, SP-B and SP-C, and [3H] -choline incorporation into total phosphatidylcholine and, type II cell specific, disaturated phosphatidylcholine in human fetal lung in culture. SP-A mRNA levels were increased by 25% and 39% in lung explants incubated in 70% and 95% oxygen, respectively, compared to levels in tissues incubated in 20% oxygen. SP-B mRNA levels were unaffected by oxygen, whereas, SP-C mRNA levels were increased by 85%, 102% and 115% in atmospheres of 35%, 50% and 70% oxygen, respectively. [3H]-choline incorporation into total phosphatidylcholine and disaturated phosphatidylcholine were both increased in human fetal lung explants incubated in increased oxygen concentrations compared to tissues incubated in 20% oxygen. Tissue levels of cyclic AMP-dependent protein kinase (PKA) activity were not affected by oxygen concentration, implying that the changes observed in surfactant protein mRNA levels and [3H]-choline incorporation may not be mediated through alterations in PKA enzyme activity. These findings demonstrate that oxygen regulates surfactant protein mRNA expression and phospholipid production in human fetal lung in vitro. We speculate that surfactant composition and, possibly, function may be regulated by oxygen in human lung. 

Received 27 January 1994; accepted in final form 22 December
1994.
APS Manuscript Number L31-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 February 1995.