STREPTOZOTOCIN DIABETES AND THE EXPRESSION OF GLUT1 AT THE BRUSH-BORDER AND BASOLATERAL MEMBRANES OF INTESTINAL ENTEROCYTES

Changes in membrane expression of sodium-dependent glucose transporter (SGLT1) and glucose transporter isoform (GLUT2) protein have been imp licated in the increased intestinal glucose transport in streptozotoci n-diabetes. The possible involvement of GLUT1 in the transport respons e, however, has not previously been studied. Using confocal microscopy on tissue sections and Western blotting of purified brush border memb rane (BBM) and basolateral membrane (BLM), we have examined enterocyte expression of GLUT1 in untreated and in 1 and 21 day streptozotocin d iabetic rats. In control enterocytes, GLUT1 was absent at the BBM and detected at low levels at the BLM. Diabetes resulted in a 4- to 5-fold increased expression of GLUT1 at the BLM and the protein could also b e readily detected at the BBM. Insulin treatment of diabetic rats incr eased GLUT1 level at the BBM but,vas without effect on expression of t he protein at the BLM.