[Effects of ginkgolide B on arachidonic acid metabolizing enzymes and level of intracellular calcium in rat polymorphonuclear leukocytes].
OBJECTIVE
To investigate the effects of ginkgolide B on arachidonic acid (AA) metabolizing enzymes and the level of intracellular calcium in rat polymorphonuclear leukocytes.


METHODS
Intracellular free calcium was quantitated by Fura-2 fluorescence technique. Phospholipase A2 (PLA2) activity was determined by incorporating 3H-arachidonic acid in leukocytes. 5-Lipoxygenase (5-LO) activity was evaluated by RP-HPLC.


RESULTS
In comparison with control, ginkgolide B at final concentration of 0.1-10 mumol.L-1 inhibited A23187 induced AA release by 10.9%-22.2%; at final concentration of 0.1-50 mumol.L-1, ginkgolide B inhibited LTB4 and 5-HETE synthesis stimulated by PAF by 29.4%-88.8% and 26.2%-89.3% respectively. At the final concentration of 0.1-100 mumol.L-1, ginkgolide B decreased the rise of intracellular calcium level induced by pletelet activating factor (PAF) and N-formyl-methionine-leucine-phenglalanine (fMLP) by 13.9%-51.4% and 2.2%-36.6%, respectively.


CONCLUSIONS
Ginkgolide B was found to significantly inhibit PLA2 and 5-LO activities, as well as the increase of the intracellular calcium induced by PAF.
Zhou
L E
LE
Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China.
Wang
W J
WJ
Bai
J Y
JY
Cheng
G F
GF
D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D016718:Arachidonic Acid / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004224:Diterpenes; D005260:Female; D046934:Ginkgolides; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D007783:Lactones / Q000494:pharmacology*; D007975:Leukotriene B4 / Q000378:metabolism; D008297:Male; D009504:Neutrophils / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D051381:Rats; D017208:Rats, Wistar
D004224:Diterpenes; D046934:Ginkgolides; D006893:Hydroxyeicosatetraenoic Acids; D007783:Lactones; D007975:Leukotriene B4; D016718:Arachidonic Acid; C022022:5-hydroxy-6,8,11,14-eicosatetraenoic acid; C045856:ginkgolide B; D001094:Arachidonate 5-Lipoxygenase; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium