Synthesis of prostanoids and cyclic nucleotides by phagocytosing rat Kupffer cells

Authors

  • Manfred BIRMELIN,

    1. Biochemisches Institut der Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 7, D-7800 Freiburg, Federal Republic of Germany
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  • Karl DECKER

    1. Biochemisches Institut der Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 7, D-7800 Freiburg, Federal Republic of Germany
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Abstract

Rat Kupffer cells in monolayer culture were allowed to phagocytose unopsonized zymosan granules. They responded with a strongly stimulated synthesis and release of prostanoids, mainly the immunologically determined prostaglandins PGE2 and PGF. The same response could be obtained by treatment with the calcium ionophore A23187. The effects of the ionophore and the zymosan particles were of the same magnitude but not additive. The rapid uptake of Ca2+ after contact with phagocytosable material recently described by us [(1983) Eur. J. Biochem. 131, 539–543] appears to mediate the enhanced prostaglandin synthesis. That response was suppressed not only by indomethacin but also by trifluoperazine which does not inhibit Ca2+ entry in the Kupffer cells. Similar effects by R24571 and 4-bromophenacyl bromide support the participation of calcium-calmodulin and of phospholipase A2.

The calcium channel blocker Verapamil® did not influence the zymosan-provoked production of prostaglandin PGE2 nor were any indications obtained for a feedback inhibition by PGE1 or PGE2.

Contact with zymosan resulted in a rapid but transient rise of the intracellular levels of cAMP and cGMP: 10 nM indomethacin completely blocked the increase of both cyclic nucleotides while trifluoperazine elicited different responses in the cAMP and cGMP levels.

The stimulated release of prostaglandin E2 was inhibited in a dose-dependent manner by nordihydroguaiaretic acid, an inhibitor of 5-lipoxygenase and by FPL 55712, known as a receptor antagonist for some leukotrienes. This suggests a regulatory role for its metabolites on prostaglandin synthesis.

Abbreviations
PGE1

PGE2 and PGF, prostaglandins E1, E2 and F

cAMP

adenosine 3′,5′-monophosphate

cGMP

guanosine 3′,5′-monophosphate

ionophore A23187

6S-[6α(2Sast;, 3S*), 8β(R*), 9β,11α]5-(methylamino)-2-[{3,9,11-trimethyl-8-[1-methyl-2-oxo-2-(1H-pyrrol-2-yl)-ethyl]-1,7-dioxaspiro[5,5]-undec-2-yl}methyl]-4-benzoxazole carboxylic acid

Hepes

4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid

FPL 55712

sodium 7-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)-2-hydroxy propoxy]-4-oxo-8-propyl-4H-1-benzopyran-2-carboxylate

NDGA

nordihydroguaiaretic acid, 4,4′-(2,3-di-methyl-tetramethylene)dipyrocatechol

R24571

1-[bis(p-chlorophenyl) methyl]-3–[2,4-dichloro-β-(2,4-dichlorobenzyloxy-)phenethyl]imidazolium chloride

SRS-A

slow-reacting substance of anaphylaxis

Enzymes
 

adenylate cyclase or ATP pyrophosphate-lyase (cyclizing) (EC 4.6.1.1)

 

cyclooxygenase or arachidonate: oxygen oxidore-ductase (cyclizing) (EC 1.14.99.1)

 

guanylate cyclase or GTP pyrophosphate-lyase (cyclizing) (EC 4.6.1.2)

 

lactate dehydrogenase or l-lactate:NAD+ oxidoreductase (EC 1.1.1.27)

 

lipoxygenase or linoleate:oxygen oxidoreductase (EC 1.13.11.12)

 

cAMP phosphodiesterase or 3′,5′-cyclic-nucleotide 5′-nucleotidohydrolase (EC 3.1.4.17)

 

phospholipase A2 or phosphatide 2-acylhydrolase (EC 3.1.1.4)

 

pronase (EC 3.4.24.4)

Ancillary