The intensity, spectrum, and polarization of gyrosynchrotron radiation from an arbitrary distribution of electrons in a magnetoactive plasma are calculated. These calculations are based on detailed theories of gyrosynchrotron emission and absorption as well as on the equations of radiation transfer in the limit of large Faraday rotation. By performing extensive numerical calculations for both isotropic and aniso- tropic electron distributions, we investigate the influence of reabsorption and the influence of a cold plasma on the spectrum and polarization of the radiation. Using the same formalism and calculations, we also investigate the possibility of negative absorption in an anisotropic gyrosynchrotron source