Acute and short-term insulin-induced molecular adaptations of GLUT2 gene expression in the renal cortex of diabetic rats.
Increased GLUT2 gene expression in the renal proximal tubule of diabetic rats is an adaptive condition, which may be important in the diabetic nephropathy development. We investigated the effects of insulin treatment upon the renal GLUT2 overexpression of diabetic rats. Acute treatment, surprisingly, induced a rapid further increase in GLUT2 mRNA content. Twelve hours after insulin injection, GLUT2 mRNA was twice the value of saline-injected rats (P<0.001), when GLUT2 protein remained unchanged. In response to short-term treatment, both GLUT2 mRNA and protein were increased in 1-day treated rats (P<0.05 versus saline-injected), decreasing after that, and reaching, within 6 days, values close to those of non-diabetic rats. Concluding, insulin treatment induced: initially, an additional upregulation of GLUT2 gene expression, involving posttranscriptional modulation; thereafter, downregulation of GLUT2 expression, which returns to non-diabetic levels. The former may be related to increased insulin concentration, the latter may be due to glycemic control.
Freitas
Helayne Soares
HS
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Av. Prof. Lineu Prestes, 1524, 05505-900 Sao Paulo, SP, Brazil.
Schaan
Beatriz D'Agord
BD
Seraphim
Patricia Monteiro
PM
Nunes
Maria Tereza
MT
Machado
Ubiratan Fabres
UF
D000222:Adaptation, Physiological; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects*; D051273:Glucose Transporter Type 2; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D007672:Kidney Cortex / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D001786:Blood Glucose; D051273:Glucose Transporter Type 2; D007004:Hypoglycemic Agents; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger