SHORTENING OF POLY(A) TAIL OF GLUCOSE-TRANSPORTER - ONE MESSENGER-RNAIN EXPERIMENTAL DIABETES-MELLITUS

To determine the molecular mechanisms of diabetes-related changes in t he expression of GLUT-1 in cerebral tissue, streptozotocin-induced dia betic rats and vehicle injected controls were studied after 4 weeks of diabetes. The GLUT-1 mass in cerebral microvessels was reduced in dia betic rats by approximately 38% (P < 0.01). The GLUT-1 concentration i n insulin-treated diabetic group was not significantly different from controls, The GLUT-1 mRNA content of cerebral tissue in diabetic rats (0.064 +/- 0.007) was significantly reduced compared to control rats ( 0.122 +/- 0.011) or insulin-treated diabetic rats (0.122 +/- 0.015) P < 0.01. The in vitro translation of GLUT-1 mRNA of diabetic rats (0.79 3 +/- 0.047 arbitrary units) was also significantly lower than that in control rats (1.403 +/- 0.153) P < 0.01 or insulin-treated diabetic r ats. (1.124 +/- 0.083) P < 0.01. These changes occurred in asssociatio n with a reduction in poly (A) tail length of GLUT-1 mRNA which decrea sed from a control value of 200-350 nt to only 50-100 nt in diabetic r ats. Shortening of poly (A) tail of mRNAs is a novel mechanism of diab etes-related changes in the expression of specific genes which are reg ulated at a translational level. (C) 1997 Elsevier Science B.V.