Glucose transporter immunoreactivity in the hypothalamus and area postrema

To study the glucose transporter (GT) protein in two glucose-sensitive areas of the rat brain, frozen coronal sections at the level of the median eminence (ME) and area postrema (AP) were stained immunocytochemically with an antibody raised against human erythrocyte glucose transporter. Immunoreactivity was mainly confined to blood vessels in most brain areas but was lacking in those of the ME and AP, which also lack a normal blood-brain barrier. This suggests that glucose entry into these brain areas, unlike others, is not limited or regulated by capillary glucose transport systems. Tancyte processes stained strongly for GT and for glycogen and thus may have an unusual glucose metabolism.