Premium
Arachidonic acid metabolism by platelets of differing size
Author(s) -
Jakubowski Joseph A.,
Thompson Craig B.,
Vaillancourt Raymond,
Valeri C. Robert,
Deykin Daniel
Publication year - 1983
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1983.00467.x-i1
Subject(s) - arachidonic acid , platelet , chemistry , mean platelet volume , thrombin , metabolism , thromboxane , centrifugation , thromboxane b2 , biochemistry , thromboxane a2 , high performance liquid chromatography , radioimmunoassay , chromatography , medicine , enzyme , receptor
S ummary . The relationship between mean platelet volume (MPV) and platelet arachidonic acid metabolism was examined by studying the ability of human platelets of different size to incorporate and metabolize tritiated arachidonic acid ([ 3 HIAA). Platelet phospholipids were labelled with [jH]AA and the platelets were then fractionated into size‐dependent subpopulations by counterflow centrifugation. The incorporation of [jH]AA increased through the fractions proportional to the MPV. After thrombin stimulation the per cent of total jH‐radioactivity released from the platelets decreased as the MPV increased. However, fractionation of the released %‐radioactivity by HPLC (high performance liquid chromatography) demonstrated that MPV had no significant influence on the per cent of total platelet 3H‐radioacti‐vity released as cyclooxygenase products or as HETE (12‐hydroxyeicosatetraenoic acid) but that the release of unmetabolized [3H]AA decreased as MPV increased. In separate experiments using unlabelled platelets the absolute release of thromboxane BL (TXB2) after collagen‐ and thrombin‐induced aggregation was measured by radioimmunoassay and was found to increase in proportion to the MPV. These results demonstrate that the release of arachidonic acid metabolites is qualitatively similar in platelets of different size. However, the absolute ability of platelets to incorporate arachidonic acid, convert it to active metabolites and release them is proportional to their volume. The ability of platelets to release unmetabolized arachidonic acid varies inversely with their MPV.