The low frequency electromagnetic fields (LF-EMF), containing the electro- magnetic fields(EMF) irradiated by High-Voltage Transmission Lines(HVTL), exist widely in our living environment, at present. The harms of LF-EMF on human health have become a considerable and concerned problem for people. In this thesis, we investigate mainly the influences of LF-EMF irradiated by HVTL on one signal transduction pathway of cell, JAK-STAT pathway. Meanwhile, the effects of LF-EMF on theβ-endorphin(EP) ex...