Kinetics of uptake and distribution of arachidonic acid by rat alveolar macrophages.
The time course of uptake and distribution of 3H-arachidonic acid (3H-AA) into rat alveolar macrophage phospholipid pools was examined. Macrophages incubated with exogenous 3H-AA in RPMI-1640 containing 0.1% bovine serum albumin (BSA), incorporated this radiolabel into phosphatidylcholine and phosphatidylinositol (PI) with plateaus reached within 2 to 4 hours, which remained relatively constant for up to 18 hours. Incorporation of 3H-AA into phosphatidylethanolamine was small, but continued to increase for 14 hours. Analysis of phosphate content in phospholipid pools revealed that treatment with exogenous 5 nM arachidonic acid had no effect upon pool sizes, but there was a selective incorporation of 3H-AA into PI. Cells were incubated with 3H-AA in RPMI alone or medium containing either 0.2% lactalbumin, fetal calf serum at variable concentrations, 10% Nu Serum, or 0.1% BSA. Incubation of macrophages with 3H-AA in RPMI alone or containing 0.2% lactalbumin, resulted in approximately 70% of the radiolabel taken up by the cells being incorporated into triglyceride. The addition of BSA to RPMI-1640 medium was found to facilitate selective uptake of 3H-AA into phospholipids. Approximately 70% of incorporated 3H-AA was releasable through the action of exogenous phospholipase A2.
Robison
T W
TW
Department of Pediatrics, University of Southern California, Childrens Hospital of Los Angeles 90027.
Duncan
D P
DP
Forman
H J
HJ
D000818:Animals; D001095:Arachidonic Acids / Q000493:pharmacokinetics*; D008055:Lipids / Q000302:isolation & purification; D008264:Macrophages / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000166:cytology*; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000494:pharmacology; D013997:Time Factors; D014316:Tritium
D001095:Arachidonic Acids; D008055:Lipids; D012709:Serum Albumin; D014316:Tritium; D010758:Phosphorus