Often there are differences in gene regulation or enzyme function of CYPs in related animals that explain observed differences in susceptibility to toxic compounds (ex. canines inability to metabolize xanthines such as caffeine).
Con frecuencia hai diferenzas na regulación xénica ou función encimática dos CYPs en animais relacionados que explican as diferenzas observadas na susceptibilidade a compostos tóxicos (por exemplo, a incapacidade dos caninos de metabolizaren as xantinas como a cafeína).