Surfactant metabolism in surfactant protein A-deficient mice.
In the present study we asked if surfactant metabolism was altered in surfactant protein (SP) A-deficient mice in vivo. Although previous studies in vitro demonstrated that SP-A modulates surfactant secretion and reuptake by type II cells, mice made SP-A deficient by homologous recombination grow and reproduce normally and have normal lung function. Alveolar and lung tissue saturated phophatidylcholine (Sat PC) pools were 50 and 26% larger, respectively, in SP-A(-/-) mice than in SP-A(+/+) mice. Radiolabeled choline and palmitate incorporation into lung Sat PC was similar both in vivo and for lung tissue slices in vitro from SP-A(+/+) and SP-A(-/-) mice. Percent secretion of radiolabeled Sat PC was unchanged from 3 to 15 h, although SP-A(-/-) mice retained more labeled Sat PC in the alveolar lavages at 48 h (consistent with the increased surfactant pool sizes). Clearance of radiolabeled dipalmitoylphosphatidylcholine and SP-B from the air spaces after intratracheal injection was similar in SP-A(-/-) and SP-A(+/+) mice. Lack of SP-A had minimal effects on the overall metabolism of Sat PC or SP-B in mice.
Ikegami
M
M
Department of Pediatrics, University of California Los Angeles School of Medicine, 90509, USA.
Korfhagen
T R
TR
Bruno
M D
MD
Whitsett
J A
JA
Jobe
A H
AH
D000818:Animals; D001835:Body Weight; D006720:Homozygote; D008168:Lung / Q000033:anatomy & histology / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D051379:Mice; D018345:Mice, Knockout; D009929:Organ Size; D010713:Phosphatidylcholines / Q000378:metabolism; D011510:Proteolipids / Q000378:metabolism / Q000502:physiology*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism* / Q000502:physiology*; D012756:Sheep
D010713:Phosphatidylcholines; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants