Role of transferrin and ceruloplasmin in antioxidant activity of lung epithelial lining fluid

E. R. Pacht, W. B. Davis

Research output: Contribution to journalArticle

84 Scopus citations

Abstract

Lung epithelial lining fluid (ELF) is a thin layer of plasma ultrafiltrate and locally secreted substances that may provide antioxidant protection and serve as a 'front-line' defense for the lower respiratory tract epithelium. To characterize the antioxidant properties of ELF, young, healthy, nonsmoking volunteers underwent bronchoalveolar lavage with determination of ELF volumes and ELF proteins. ELF (>0.4 ml) is a potent inhibitor of lipid peroxidation as measured by malondialdehyde (MDA) production in an in vitro iron-dependent assay system. Two serum proteins, transferrin and ceruloplasmin, were quantitated in ELF and found to be potent inhibitors of lipid peroxidation. Other ELF components, including vitamin E, vitamin C, and albumin, did not function as antioxidants in this system. Several experimental observations suggests that ELF transferrin was more important than ceruloplasmin in inhibiting lipid peroxidation: 1) ELF concentrations of transferrin were 20-fold higher than those for ceruloplasmin; 2) ELF antioxidant activity was abolished by preincubation with Fe3+; 3) ELF antioxidant activity was mimimally affected by sodium azide, which is known to inhibit cerluloplasmin ferroxidase activity; and 4) ELF ceruloplasmin ferroxidase activity was virtually nondetectable. ELF possesses a significant antioxidant activity that may be important in vivo in protecting the lung from oxidant injury.

Original languageEnglish (US)
Pages (from-to)2092-2099
Number of pages8
JournalJournal of Applied Physiology
Volume64
Issue number5
Publication statusPublished - Jan 1 1988

    Fingerprint

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this