Changes in sodium or glucose filtration rate modulate expression of glucose transporters in renal proximal tubular cells of rat.
Renal glucose reabsorption is mediated by luminal sodium-glucose cotransporters (SGLTs) and basolateral facilitative glucose transporters (GLUTs). The modulators of these transporters are not known, and their substrates glucose and Na+ are potential candidates. In this study we examined the role of glucose and Na+ filtration rate on gene expression of glucose transporters in renal proximal tubule. SGLT1, SGLT2, GLUT1 and GLUT2 mRNAs were assessed by Northern blotting; and GLUT1 and GLUT2 proteins were assessed by Western blotting. Renal cortex and medulla samples from control rats (C), diabetic rats (D) with glycosuria, and insulin-resistant 15-month old rats (I) without glycosuria; and from normal (NS), low (LS), and high (HS) Na+-diet fed rats were studied. Compared to C and I rats, D rats increased (P < 0.05) gene expression of SGLT2 by approximately 36%, SGLT1 by approximately 20%, and GLUT2 by approximately 100%, and reduced (P < 0.05) gene expression of GLUT1 by more than 50%. Compared to NS rats, HS rats increased (P < 0.05) SGLT2, GLUT2, and GLUT1 expression by approximately 100%, with no change in SGLT1 mRNA expression, and LS rats increased (P < 0.05) GLUT1 gene expression by approximately 150%, with no changes in other transporters. In summary, the results showed that changes in glucose or Na+ filtrated rate modulate the glucose transporters gene expression in epithelial cells of the renal proximal tubule.
Vestri
S
S
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Okamoto
M M
MM
de Freitas
H S
HS
Aparecida Dos Santos
R
R
Nunes
M T
MT
Morimatsu
M
M
Heimann
J C
JC
Machado
U F
UF
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism; D004032:Diet; D005786:Gene Expression Regulation; D005919:Glomerular Filtration Rate; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D051273:Glucose Transporter Type 2; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism*; D051269:Sodium-Glucose Transporter 1; D051297:Sodium-Glucose Transporter 2
D051272:Glucose Transporter Type 1; D051273:Glucose Transporter Type 2; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; C495679:Slc2a1 protein, rat; C495676:Slc5a1 protein, rat; C490300:Slc5a2 protein, rat; D051269:Sodium-Glucose Transporter 1; D051297:Sodium-Glucose Transporter 2; D012964:Sodium; D005947:Glucose