Stimulation of arachidonic acid metabolism by a streptococcal preparation (OK-432) in rat peritoneal macrophages.
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 micrograms/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 phagocytotic 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 biological effects is discussed.
Watanabe
M
M
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan.
Shishido
Y
Y
Hirasawa
N
N
Mue
S
S
Fujiki
H
H
Ohuchi
K
K
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002460:Cell Line; D003571:Cytochalasin B / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis; D006358:Hot Temperature; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010529:Peritoneal Cavity / Q000166:cytology; D010844:Picibanil / Q000494:pharmacology*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D016718:Arachidonic Acid; D010844:Picibanil; D003571:Cytochalasin B; D015232:Dinoprostone