Effects of ornithine on neutrophil (PMN) free amino acid and ?-keto acid profiles and immune functions in vitro

The objective of this study was to determine the effects of ornithine on polymorphonuclear leucocyte (PMN) free amino- and α-keto acid profiles, superoxide anion (O^sub 2^^sup -^) generation, hydrogen peroxide (H^sub 2^O^sub 2^) formation and released myeloperoxidase acitivity (MPO). Exogenous ornithine significantly increased PMN asparagine, glutamine, asparatate, glutamate, arginine, citrulline, alanine, α-ketoglutarate and pyruvate as intracellular ornithine increased. Concerning PMN immune function markers ornithine increased H^sub 2^O^sub 2^-generation and MPO acitivity while O^sub 2^^sup -^-formation was decreased. We believe therefore that ornithine is important for affecting PMN "susceptible free amino- and α-keto acid pool" although the mechanisms are not yet clear. This may be one of the determinants in PMN nutrition considerably influencing and modulating PMN host defense capability.[PUBLICATION ABSTRACT]