RESUMEN
Nitric oxide ( NO ) is now recognized as a mediator of several biological and immunological functions, but unlike classical neurotransmitters, NO simply diffuse of the postsynaptic cell and around affecting cells. Human chorionic gonadotropin ( hCG ), produced by placental trophoblasts may act as stimulator on NO synthesis in oocytes of mouse's ovary. How-ever, in the various organs or cells, the action of hCG on NO synthesis is unknown. We have examined that the effect of hCG on NO synthesis in microglial cells of murine's brain, using the Griess method. And this study was evident that hCG did not induce NO produc-tion without recombinant interferon gamma ( rIFN-gamma), whereas hCG ( 10~500 IU/ml ) with rIFN-gamma effectively produced NO in microglial cells of brain. As result, NO production in microglial cells increased most significantly in dose of 100 IU/ml of the hCG and the pro-duction of NO was dependent on the dose of hCG ( Table 1 and Fig. 1 ). And N(G)-monomethyl-L-arginine ( N(G)MMA ), competitive inhibitor of NO synthase, reduced the NO production by hCG stimulation with rIFN-gamma in microglial cells of murine. Conclusively, this study sugge-sted that hCG stimulate NO production at microglial cells in brain, which may be an important factor for mediating immune and neuroendocrinologic regulation in nervous system.