The degradation of platelet-activating factor by high-density lipoprotein in rat plasma. Effect of ethynyloestradiol administration.
The degradation of platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in human plasma is brought about by a specific acetylhydrolase that is associated with low-density lipoprotein. In this study, the presence of a similar activity on high-density lipoprotein (HDL) of rat plasma has been demonstrated which is independent of lecithin-cholesterol acyltransferase (LCAT) activity. Furthermore, PAF acetylhydrolase activity may be decreased by 66% by treatment of rats with 17 alpha-ethynyloestradiol (1 mg/kg body wt.; 5 days). This treatment also decreased HDL cholesterol concentrations by 90%, but did not affect LCAT activity. Thus rat LCAT and PAF acetylhydrolase are associated with different subspecies of HDL.
Department of Pathology, University of British Columbia, Vancouver, Canada.
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Pritchard
D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D000818:Animals; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D006801:Humans; D008055:Lipids / Q000097:blood; D008075:Lipoproteins, HDL / Q000097:blood*; D008297:Male; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000037:antagonists & inhibitors / Q000097:blood; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism; D010972:Platelet Activating Factor / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D008055:Lipids; D008075:Lipoproteins, HDL; D010972:Platelet Activating Factor; D004997:Ethinyl Estradiol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase