SLC2A1 and neoplasm: However, the GlcN-PAA-UGONs exhibited no such drastic contrast enhancements in the bladder (Figure 10b), indicating their slower excretion through the renal system, compared with PAA-UGONs, owing to their uptakes by GLUT and SGLT transporters expressed on the normal and tumor cell membranes [13,14,15].