The glucose transport across the mammalian plasma membranes is carried out by members of two distinct gene families, $Na^+$/glucose to transporter (SGLT) and glucose transporters (GLUTs). The energy requiring SGLT utilizes the sodium gradient to transport glucose and galactose against the concentration gradient. The energy independent transport (Facilitative transport) of glucose down the concentration gradient is mediated by the members of GLUTs. The facilitated transport of glucose is saturable, sterospecific and bidirectional across the membrane. To date, 6 kinds of isoforms of facilitative glucose transporters are found. These proteins are expressed in a tissue and cell specific manner, and shows distinct properties that reflect their specific functional roles.