Members of solute carrier family 2 (SLC2) are facilitative glucose transporters (GLUTs), a family of integral membrane glycoproteins that transport glucose into most cells. SLC2A8, also known as GLUT8, is highly expressed in the human testis. Its expression in the testis is downregulated by estrogen treatment. Therefore, SLC2A8 is a unique glucose transporter that appears to be involved in hormonally regulated testicular function. Increased SLC2A8 expression has also been observed in endometrial adenocarcinoma, where it is thought to supply the high glucose flux needed to feed proliferating tumor cells.