IFNGFP model is represented in black. IFNGFPApo modifications over the basic IFNGFP model are drawn in grey. Common model process equivalences: kNUNC, first order rate constant of degradation of DNA; kINT, first order rate constant controlling the formation and elimination of DNA’; kS1 and kS2, first order rate constants of expression of mRNA from DNA and DNA’, respectively; kDEG, first order rate of degradation of mRNA; kTRAN, first order constant rate of transit; kS and kD, first order rate constants of synthesis and degradation of the hepatic protein; kls and ksl first order rate constants of distribution between liver and serum compartments; ksbr, first order rate constants of brain input; kE, first order rate of degradation of brain IFN; kS_ISG and kD_ISG, the first order process of synthesis and degradation in liver or brain. Specific parameter of the IFNGFPApo model: ksp and kps, distribution rate constants between central serum compartment and peripheral compartment, respectively.