| Research Abstract |
In kidney proximal tubules, D-glucose is transported from the lumen to the blood via two-step processes : Na+-dependent/independent glucose transporters (SGLT1, 2/GLUTI, 2) at both apical and basolateral membranes, respectively. In kidney tubules of distal portions, only GLUT1 is expressed at the basolateral membrane to absorb D-glucose from the blood. Using Northern blot analysis we investigated the changes of the SGLT1, SGLT2, and GLUTi mRNA expressions in neonatal rat kidney tubules during early developmental period (4-15 days). A level of SGLTImRNA expression increased on the process of development : 100% (5 d), 330% (10 d), and '720% (15 d). Secondarily, a level of SGLT2 mRNA expression increased : 100% (5 d), 280% (10 d), and 42% (15 d). Finally, a level of GLUT1 mRNA expression increased : 100% (5 d), 118% (10 d), and 132% (15 d). Injection of betamethasone (60mug/100 g body wt. , i. p.) increased the level of SGLT1, SGLT2, and GLUTi mRNA expressions by 4-9 (5-day-old rats) and by 2-3 (15-day-old rats). These results indicate that the expression of Na+-dependent /independent glucose transporters mRNA increased during the developmental period of 4-15 days and strongly suggest that betamethasone is more effective in induction of the expression of the glucose transporters at earlier period of neonates.
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