Insulin-regulated facilitative hexose transporter that mediates the transport of glucose and fructose (PubMed:10671487). Also able to mediate the transport of dehydroascorbate (PubMed:23396969). D-glucose(out) = D-glucose(in) D-fructose(out) = D-fructose(in) L-dehydroascorbate(out) = L-dehydroascorbate(in) Inhibited by cytochalasin B. Interacts with AP2B1. Principally intracellular (PubMed:10671487). May move between intracellular vesicles and the plasma membrane (PubMed:10671487). The dileucine internalization motif is critical for intracellular sequestration (PubMed:10671487). Highly expressed in adult and pubertal testis, but not prepubertal testis (PubMed:10821868). Moderate expression in hypothalamus, cerebellum, brainstem, hippocampus, and adrenal gland (PubMed:10821868). Lower amounts present in most other tissues (PubMed:10821868). Belongs to the major facilitator superfamily. Sugar transporter (TC 2.A.1.1) family. Glucose transporter subfamily.