Dynamics of uptake and channeling of arachidonic acid in hamster alveolar macrophages and the effect of bleomycin on arachidonyl distribution.
The uptake and distribution of [14C]-arachidonic acid (AA) by primary culture hamster alveolar macrophages (AM) were examined. The macrophages were incubated for 2 to 18 hrs in RPMI-1640 medium containing 0.1% BSA and [14C]-AA. The uptake of [14C]-AA by AM was rapid with 71% and 83% of exogenous [14C]-AA taken up after 2 and 4 hrs of incubation, respectively. Initially, the uptaken [14C]-AA was equally distributed between phospholipids (PL) and neutral lipids (NL). However, by 8 hrs, 86% and 14% of [14C]-AA was found in PL and NL, respectively. This distribution pattern remained constant through 18 hrs. Within the PL pool, most of the [14C]-AA was initially incorporated into phosphatidylcholine (PC). However, with time, as the percent of [14C]-AA incorporated in PC declined, the percent incorporated in phosphatidylethanolamine increased. The incorporation of [14C]-AA into sphingomyelin, phosphatidylinositol, and phosphatidylserine remained constant with time. Within the NL, most of the [14C)-AA was initially found incorporated into triacylglycerols (TG). After 4 hrs, the percent of [14C]-AA found in TG decreased markedly, while the percent found in cholesterol esters markedly increased. Incubation of AM prelabeled with [14C]-AA with bleomycin at 0.5, 5, 50 and 500 microM for 2 and 8 hrs failed to have any effect on the distribution of [14C]-AA in PL and NL pools.
Department of Veterinary Pharmacology, School of Veterinary Medicine, University of California, Davis 95616.
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Rose
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Giri
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Hyde
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D001761:Bleomycin / Q000494:pharmacology*; D002470:Cell Survival; D002478:Cells, Cultured; D006224:Cricetinae; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008647:Mesocricetus; D010743:Phospholipids / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism*
D001095:Arachidonic Acids; D010743:Phospholipids; D001761:Bleomycin