Calcium-ionophore-induced formation of platelet-activating factor and leukotrienes by horse eosinophils: A comparative study

R. Asmis, A. Jorg

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Horse eosinophils preincubated with 3H-labelled acetate and stimulated with the Ca2+ ionophores ionomycin or A23187 form a radioactive compound, which we have shown to be 1-O-alkyl-2-[3H]acetyl-sn-glycero-3-phosphocholine (platelet-activating factor). We could detect no 1-O-acyl-2-[3H]acetyl-glycero-3-phosphocholine in the radioactive fraction. The formation of platelet-activating factor was strongly correlated to the generation of leukotriene C4, the main arachidonate metabolite in horse eosinophils, suggesting that platelet-activating factor and leukotriene C4 have a common precursor pool (1-O-alkyl-2-arachidonyl-glycero-3-phosphocholine) and a common regulation of synthesis. Even though both ionomycin and A23187 are described as Ca2+ ionophores, they have a series of significantly different effects on the eosinophils with respect to formation of platelet-activating factor and leukotriene C4. While A23187 induces an asymptotic maximum of mediator formation at concentrations higher than 20 μM, ionomycin expressed a narrow optimum at 2 μM. The effects of exogenous pH on the release of mediators also differ strongly between the two ionophores: for A23187 the effects are the same for both mediators but when ionomycin is used as stimulant, generation of platelet-activating factor and leukotriene C4 are affected differently.

Original languageEnglish (US)
Pages (from-to)475-480
Number of pages6
JournalEuropean Journal of Biochemistry
Volume187
Issue number3
StatePublished - 1990
Externally publishedYes

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Calcium Ionophores
Leukotrienes
Platelet Activating Factor
Leukotriene C4
Eosinophils
Ionomycin
Horses
Calcimycin
Phosphorylcholine
Ionophores
Metabolites
Acetates

ASJC Scopus subject areas

  • Biochemistry

Cite this

Calcium-ionophore-induced formation of platelet-activating factor and leukotrienes by horse eosinophils : A comparative study. / Asmis, R.; Jorg, A.

In: European Journal of Biochemistry, Vol. 187, No. 3, 1990, p. 475-480.

Research output: Contribution to journalArticle

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