“…Consequently, this polarized distribution of ENT1 and ENT2 establishes a Na +independent transepithelial transport pathway to deliver xenobiotics across the BTB into the male genital tract for treating viral infections, cancers, and other testicular DMD-MR-2022-001186R1 indications. One such example of a nucleoside analog therapeutic used to treat leukemias, which can reside in the sanctuary site afforded by the BTB (Bowman et al, 1984;Chu et al, 1982;Gajjar et al, 1996;Grundy et al, 1997;Heaney et al, 1983;Kulkarni et al, 2010;Nesbit et al, 1980;Ritzen, 1990;Shaffer et al, 1992;Tombolini et al, 1986), is clofarabine. It is also known to cause toxicities in many organs, including in the seminiferous tubules of rodents and canines (U.S. Food and Drug Administration, 2004).…”