The ontogeny of the GLUT3 glucose transporter gene and protein expression was studied in rat brain. Northern blot analysis using total RNA from rat brains at different developmental stages revealed that the levels of GLUT3 mRNA were very low during the embryonic stage and increased towards the postnatal stage. Immunohistochemistry using a specific antibody showed that the expression of GLUT3 protein was barely detectable in the embryonic stage, but was clearly detected on the plasma membrane of neuronal cells from 10 days after birth to the adult. Expression of GLUT3 mRNA and protein in the cerebral neuronal cell cultures was also examined during the maturation of neurons. GLUT3 glucose transporter of primary neuronal cultured cerebral cortical neurons was only detected in mature neurons after they were cultured for 14 days. These results indicate that GLUT3 plays an important role in glucose homeostasis postnatally in neurons of the rat brain.
