REGULATION OF GLUCOSE TRANSPORTERS (GLUT-1 AND GLUT-3) IN HUMAN RETINAL ENDOTHELIAL-CELLS

The regulation of glucose transporters (GLUT-I and GLUT-3), in terms o f both mRNA and protein, in human retinal endothelial cells was invest igated. The cells responded within 1 h of exposure to 5 mM glucose wit h an increase in the level of GLUT-3 mRNA that was due to an increase in the transcription of the 4.1 kb mRNA of the gene for GLUT-3. In the absence of glucose, the gene for GLUT-I was not transcribed but the l evel of GLUT-3 mRNA was increased in these conditions and this was the result of an increase in the transcription of the 4.1 kb mRNA. The le vel of GLUT-1 and GLUT-3 mRNA was maximal when the cells were exposed to 15 mM glucose. These results are discussed in the light of the gluc ose regulatory potential of the retinal microvasculature and the impli cations that this may have for the mechanisms of diabetic retinopathy.