Metabolism of platelet-activating factor (alkylacetylphosphocholine) by type-II epithelial cells and fibroblasts from rat lungs

Raj Kumar, Richard J. King, Helen M. Martin, Donald J. Hanahan

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The uptake and metabolism of 3H-labeled platelet-activating factor by interstitial and epithelial cells from rat lungs was investigated. The uptake of 1-O-[3H]octadecyl-2-acetyl-sn-glycero-3-phosphocholine (3HACEPC) by alveolar type-II cells was linear with time from 5 to 60 min, with an average rate of 660 and 450 fmol/106 cells for cells in primary culture for 48 to 72 h, respectively. AGEPC was rapidly metabolized and by 10 min 60% of AGEPC was converted into long-chain acylphosphatidylcholine (PC) (50%) and 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine (lyso-GEPC) (10%). By 60 min radioactivity in AGEPC was less than 10% of the total intracellular activity. Lyso-GEPC remained at about 10% throughout the incubation period. The uptake of 3H-AGEPC by fibroblasts was very similar to type II cells, but the rate of metabolism was slower. AGEPC in fibroblasts constituted 85% of the cellular counts after 10 min of incubation, and 50% by 60 min. After 60 min only 30% of the AGEPC was converted to alkylacyl-PC. Characterization of the fatty acids in the alkylacyl-PC of both the type-II cells and lung fibroblasts indicated that arachidonic acid was preferentially (more than 90%) inserted at the 2-position.

Original languageEnglish (US)
Pages (from-to)33-41
Number of pages9
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume917
Issue number1
DOIs
StatePublished - Jan 13 1987

Keywords

  • (Rat lung)
  • Platelet-activating factor
  • Type II cell

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

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