Phorbol Myristate Acetate Stimulates Degradation of a Structural Analogue of Platelet-Activating Factor to a Neutral Lipid in Human Leukemic K562 Cells: Relevance to the Release of Lipids
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Accession number;04A0042344
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| Title;Phorbol Myristate Acetate Stimulates Degradation of a Structural Analogue of Platelet-Activating Factor to a Neutral Lipid in Human Leukemic K562 Cells: Relevance to the Release of Lipids |
| Author;
TSUTSUMI T
(Kyushu Univ. Health And Welfare, Miyazaki, Jpn)
TOKUMURA A
(Univ. Tokushima, Tokushima, Jpn)
YAMAGUCHI M
(Keio Univ., Tokyo, Jpn)
KITAZAWA S
(Nihon Univ., Chiba, Jpn)
TANIGAWARA Y
(Keio Univ., Tokyo, Jpn)
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Journal Title;Biol Pharm Bull
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Journal Code:S0989A
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ISSN:0918-6158
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VOL.27;NO.1;PAGE.24-28(2004)
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| Figure&Table&Reference;FIG.2, TBL.2, REF.29 |
| Pub. Country;Japan |
| Language;English |
| Abstract;In our attempt to investigate the mechanism of the release of platelet-activating factor (PAF) from cells, the erythroleukemic cell line K562 was preloaded with a radiolabeled PAF analogue having an ethylcarbamyl residue, 1-O-octadecyl-2-O-ethylcarbamyl-sn-glycero-3-phosphocholine (ethylcarbamyl-PAF), that is resistant to the hydrolytic action of PAF acetylhydrolase. Its extracellular release was monitored using an albumin back-extraction method, and its metabolic degradation was analyzed by TLC. Phorbol myristate acetate (PMA) was found to stimulate the release of two radioactive lipids, ethylcarbamyl-PAF itself and its metabolite, 1-O-octadecyl-2-ethylcarbamyl-sn-glycerol, whereas only ethylcarbamyl-PAF was released from the resting cells. The increased release of radioactive lipids in PMA-stimulated cells was suggested to be due to stimulated degradation of intracellular ethylcarbamyl-PAF into the cell-permeable metabolite. Thus K562 cells have much less capacity to release intact PAF-like lipid in comparison with its high ability to uptake exogenously added PAF analogues previously described by us and others. (author abst.) |
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