Deoxythymidine pools of human skin and guinea pig organs

The activity of antiviral nucleoside analogues like acyclovir is influenced by a number of cellular factors, one being the deoxythymidine (dThd) concentration. We therefore analysed the dThd concentration in human plasma and skin and in organs of guinea pig, the common experimental animal. High-performance liquid chromatography showed low amounts of dThd in human skin, 0.20-1.15 nmol/g, whereas guinea pig skin and spleen had 20-30 nmol/g and the concentration in guinea pig plasma was 10-times higher than in human plasma. These animals are therefore in this respect less suitable as accurate models for antiviral nucleoside activity in humans.