Expression of Nucleoside Transporters in the Mouse Testis and Ovary

Nucleoside transporters play key roles in the physiology of nucleosides and nucleobases in mammals and also contribute to the pharmacological actions produced by their analogs. Several mammalian nucleoside transporters have been identified at the molecular level. The aim of this study was to examine the expression of the major nucleoside transporter isoforms in the mouse testis and ovary. Equilibrative Nucleoside Transporter 1 (ENT1) and ENT2 were expressed in the mouse testis and ovary, which was consistent with the general consideration that these transporters are ubiquitous in mouse tissues. The expression of Concentrative Nucleoside Transporter 2 (CNT2) and CNT3, but not CNT1 was detected in the mouse testis. These three CNT isoforms were also expressed in the ovary. Therefore, we concluded that the mouse testis and ovary simultaneously exhibit multiple transport processes for nucleosides and bases and also that these transporters are responsible for the homeostatic control of biological levels of nucleosides and bases in these tissues.