Phosphatidylcholine resynthesis from components of internalized phospholipids in rat granular pneumocytes in primary culture
Uptake, degradation and reutilization of surfactant phospholipids was investigated by incubating granular pneumocytes in primary culture with 0.2 mM liposomal phosphatidylcholine containing (/sup 3/H-methyl)choline labeled dipalmitoyl PC. Trypsin-resistant cell associated liposome radioactivity in PC declined steadily with time of incubation to 50% of total radioactivity by 140 min. In the water soluble fraction, most of the radioactivity was present in glycerophosphorylcholine which increased steadily to 13% of total cell associated radioactivity. While the proportion of radioactivity in choline remained unchanged, it increased with time in CDP-choline and phosphorylcholine suggesting reutilization of choline for PC resynthesis. In lamellar bodies isolated from these cells, less than 10% of PC label was present in unsaturated PC. In the microsomal fraction the label in unsaturated PC at 21 min was 56% of total PC which increased to 71% by 140 min of incubation with liposomes (slope = 0.19%/min; r = 0.67) suggesting metabolic reutilization of dipalmitoyl PC in this compartment. These observations indicate that granular pneumocytes degrade internalized PC and resynthesize PC de novo from degradation products.
- Research Organization:
- Univ. of Pennsylvania School of Medicine, Philadelphia
- OSTI ID:
- 5272428
- Report Number(s):
- CONF-8606151-; TRN: 86-031425
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LEUKOCYTES
BIOLOGICAL FUNCTIONS
PHOSPHOLIPIDS
BIOSYNTHESIS
CELL CULTURES
CHOLINE
MICROSOMES
RADIOACTIVITY
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL CONSTITUENTS
DRUGS
ESTERS
FUNCTIONS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
LIPOTROPIC FACTORS
MAMMALS
MATERIALS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
QUATERNARY COMPOUNDS
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques