Testis-specific transporter

Testis-specific transporters TST-1 and TST-2 have been reported to transport thyroid hormones [26]. Further studies are required to clarify the functions of TST-1 and TST-2. 

The human gonad-specific transporter OATP6A1 is expressed at high level in the testis. It consists of 719 amino adds. OATP6A1 is relatively close to Oatp4al/... 

The existence of a barrier between the blood and testes is indicated by the absence of staining in testicular tissue after the intravascular injection of dyes. Morphological studies indicate that the barrier lies beyond the capillary endothelial cells and is most likely to be found at the specialized Sertoli-Sertoli cell junction. It appears that Pgp, the efflux transporter protein, also plays a role in forming this blood-testis barrier. This protein probably plays a role in preventing certain chemotherapeutic agents from reaching specific areas of the testis and thus hinders treatment of the neoplasm. 

BCRP (ABCG2) The breast cancer resistance protein (BCRP) transporter is also known as mitoxantrone resistance (MXR) protein (Miyake et al., 1999 Krishnamurthy and Schuetz, 2006). BCRP is expressed in plasma membrane of placental syncytiotrophoblasts of the chorionic villus (Mao, 2008 Robey et al., 2009), mammary glands, testis, canicular membrane of hepatocytes, cortical and proximal tubules in the kidney, villous tip of intestinal cells in the small intestine, hematopoietic stem cells, endothelial cells of venules and capillaries, and the luminal surface of the endothelial cells at the blood-brain barrier. The substrate specificity for BCRP overlaps broadly with P-gp therefore, the clinical DDI implications for BCRP are as yet not well defined. The current limited data suggest that BCRP may have an impact on chemoresistance in cancer (Noguchi et al., 2009). Rosuvastatin and topotecan have been reported to increase plasma AUC for antivirals and cyclosporins (Allen et al., 2002 Maliepaard et al., 2001, Table 4.8). 

---