Enhanced arachidonic acid and calcium metabolism in cholesteryl sulfate-enriched rat platelets.
We previously found that cholesteryl sulfate (CS), a minor lipid constituent, is present in blood platelets and might influence platelet aggregation. In this study, we investigated whether CS modifies platelet arachidonic acid and calcium metabolism. In CS-loaded rat platelets, we found a potentiation of the arachidonate-induced aggregation, an increase in the thrombin-induced release of radiolabeled arachidonate preincorporated into platelet phospholipids and an increased formation of cyclooxygenase and lipoxygenase products. In addition, the calcium uptake in non-stimulated as well as in thrombin-stimulated CS-loaded platelets was enhanced. The above-mentioned effects were never observed with cholesterol, cholesteryl acetate, estrone and estrone sulfate. Although the precise determinants for the platelet CS concentration are not presently known, our findings might suggest a new role for CS as a modulator of the activity of these cells.
Blache
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INSERM CJF 93-10, Laboratoire de Biochimie des Lipoprotéines, Université de Bourgogne, Dijon, France.
D000818:Animals; D016718:Arachidonic Acid / Q000097:blood* / Q000494:pharmacology; D001792:Blood Platelets / Q000737:chemistry / Q000378:metabolism*; D002118:Calcium / Q000097:blood*; D002788:Cholesterol Esters / Q000494:pharmacology*; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects; D051381:Rats; D013917:Thrombin / Q000494:pharmacology; D013929:Thromboxane B2 / Q000096:biosynthesis
D002788:Cholesterol Esters; D016718:Arachidonic Acid; D013929:Thromboxane B2; D013917:Thrombin; C007045:cholesteryl sulfate; D002118:Calcium