High expression levels of the "erythroid/brain" type glucose transporter (GLUT1) in the basal cells of human eye conjunctiva and oral mucosa reconstituted in culture.

The expression of the "erythroid/brain" type glucose transporter (GLUT1) seems to be a feature of "barrier" tissues, at least in humans. Recently, we reported that GLUT1 is highly expressed in the basal layers of either "authentic" human epidermis or human epidermis reconstituted in culture and that its expression seems to be related to keratinocyte differentiation. In this paper we demonstrate that GLUT1 is selectively expressed in the basal layers of either eye conjunctiva epithelia or oral mucosa, reconstituted in culture starting from 1-2 mm2 bioptic specimens of normal human tissue. GLUT1 mRNA and protein levels are very high in conjunctiva and oral mucosa, 2-3 times higher than in epidermis reconstituted in culture. Taking into account its localization at the border of tissues not directly vascularized, but metabolically active, GLUT1 could play an important role in controlling the entry of glucose into these firmly guarded tissues.