Stimulation of arachidonic acid metabolism by a streptococcal preparation (OK-432) in rat peritoneal macrophages

Masako Watanabe, Yoshiyuki Shishido, Noriyasu Hirasawa, Suetsugu Mue, Hirota Fujiki, Kazuo Ohuchi

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2 Citations (Scopus)


A streptococcal preparation OK-432 is reported to be an immunopotentiator and a potent antitumor agent. In order to elucidate the mechanism of biologic action, effects of OK-432 on arachidonic acid metabolism in rat peritoneal macrophages were investigated. Prostaglandin E2 production and release of radioactivity from [3H]arachidonic acid-labeled macrophages were found to be stimulated by OK-432 in a concentration-dependent manner (5 to 80 μg/ml). Heat-treatment of OK-432 further stimulated its effects. These stimulative effects on arachidonic acid metabolism by OK-432 were not observed in MDCK cells that have no phagocytic activity. Furthermore, cytochalasin B treatment completely suppressed the stimulative effects induced by OK-432 in macrophages. These results strongly indicate that the stimulative effects by OK-432 on arachidonic acid metabolism are dependent on phagocytosis of OK-432 particles. Significance of stimulation of arachidonic acid metabolism in macrophages by OK-432 for its bioligical effects is discussed.

Original languageEnglish
Pages (from-to)157-161
Number of pages5
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Issue number2
Publication statusPublished - 1992 Feb 14


  • (Rat peritoneal macrophage)
  • Arachidonic acid
  • Cytochalasin B
  • OK-432
  • Phagocytosis
  • Prostaglandin E


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