Thyrotropin-releasing hormone enhances the superoxide anion production of rabbit peritoneal macrophages stimulated with N-formyl-methionyl-leucyl-phenylalanine and opsonized zymosan.
Effects of thyrotropin-releasing hormone (TRH) on the superoxide anion (O2-) production, which is essential for effective microbicidal and cytotoxic activity in macrophages (M phi s), were investigated. TRH by itself failed to induce the O2- production of rabbit peritoneal M phi s elicited with thioglycollate medium. However, M phi s preincubated with TRH showed the significant enhancements of O2- production following stimulation with the chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP), at TRH concentrations from 10(-7) to 10(-4) M with a peak enhancement at 10(-5) M. O2- generations of M phi s stimulated with opsonized zymosan (OZ) were also enhanced at TRH concentrations from 10(-10) to 10(-5) M with a peak enhancement at 10(-7) M. Maximal enhancements of O2- production were obtained with 10 min preincubation with TRH both for FMLP and OZ stimulations. TRH had no effect on O2- production when stimulated with phorbol 12-myristate 13-acetate. Thyrotropin did not augment the O2- production induced with either FMLP or OZ. These results indicate that TRH has the priming effect on FMLP- and OZ-induced O2- production of rabbit peritoneal M phi s, although the mechanism remains to be clarified.
National Biomedical Center for Spin Trapping and Free Radicals, Free Radical Biology, Oklahoma Medical Research Foundation, Oklahoma City 73104.
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Koshida
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Kotake
D000595:Amino Acid Sequence; D000818:Animals; D003574:Cytochrome c Group / Q000378:metabolism; D005260:Female; D007700:Kinetics; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D010529:Peritoneal Cavity / Q000166:cytology; D011817:Rabbits; D013268:Stimulation, Chemical; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D015054:Zymosan / Q000276:immunology / Q000494:pharmacology*
D003574:Cytochrome c Group; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D013973:Thyrotropin-Releasing Hormone; D015054:Zymosan; D013482:Superoxide Dismutase