Metabolic fate of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) and lyso-PAF (1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine) in FRTL5 cells.
The metabolism of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) and lyso-PAF (1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine) was investigated in FRTL5 cells, a normal rat thyroid cell line. FRTL5 cells incorporated [3H]PAF and deacetylated this compound to the corresponding [3H]lyso-PAF which was not accumulated or secreted but converted mainly to alkyl-acyl-phosphocholine indicating that this acylation process was particularly active in these cells. Among metabolic products of both [3H]PAF and [3H]lyso-PAF were alkylglycerol as well as its mono- and diacyl derivatives. [3H]alkylglycerol could be the intermediate compound for the production of [3H]alkyl- and [3H]alkenyl-phosphoethanolamine (plasmalogen) which were also metabolic products. FRTL5 cells were able to convert lyso-PAF to PAF especially when they were stimulated by ionophore A23187 in the presence of [3H]Iyso-PAF and phenylmethylsulfonyl fluoride. The amount of PAF increased for the first 30 min and declined thereafter. PAF resting levels were found low in the same cells. Furthermore, PAF-acetylhydrolase activity was determined in cell homogenates. The presence of metabolic products such as alkyl-phosphatidylcholine, alkyl- and alkenyl-phosphatidylethanolamine and alkyl-glycerol, as well as, its mono- and diacyl derivatives, indicates that FRTL5 cells and probably other thyroid cells, are very active in metabolizing PAF and lyso-PAF and suggests the co-operation of the corresponding metabolic pathways in these cells.
Botitsi
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E
Department of Chemistry, University of Athens, Greece.
Mavri-Vavayanni
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M
Siafaka-Kapadai
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A
D000107:Acetylation; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D007700:Kinetics; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D010713:Phosphatidylcholines / Q000378:metabolism*; D010955:Plasmalogens / Q000378:metabolism; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D051381:Rats; D013961:Thyroid Gland; D014316:Tritium
C029271:O-deacetyl platelet activating factor; D010713:Phosphatidylcholines; D010955:Plasmalogens; D010972:Platelet Activating Factor; D014316:Tritium; D000001:Calcimycin; D010664:Phenylmethylsulfonyl Fluoride