Renal IGF-1 mRNA levels are enhanced following unilateral nephrectomy in immature but not adult rats.
The increase in IGF-1 gene expression following unilateral nephrectomy (UNX) in adult rats is controversial. In this study we have examined whether developmental differences exist in the effect of UNX on IGF-1 gene expression. Immature (23 days) and adult (4 months) Wistar rats underwent a sham operation or left UNX, and were sacrificed 24 or 48 hrs later. IGF-1 mRNA levels were determined in left (control) and right (compensated) kidneys using solution hybridization/RNase protection assays. By 48 hrs post-UNX, remnant kidneys had grown 20 +/- 1% in adult rats (P less than 0.05), and 69 +/- 5% in immature rats (P less than 0.05). IGF-1 mRNA levels were not increased in the adult compensated kidneys at either 24 or 48 hrs post-UNX. In contrast, kidneys from immature rats 24 and 48 hrs post-UNX had an average 4-fold increase (P less than 0.05) in exon 1 IGF-1 mRNA levels, and an average 3-fold increase (P less than 0.05) in exon 2 mRNA levels. Thus, these findings suggest that there is an age-dependent difference in the effects of UnX on IGF-1 gene expression, and provide the first evidence that IGF-1 gene expression increases following unilateral nephrectomy in immature rats.
Mulroney
S E
SE
Department of Physiology and Biophysics, Georgetown University School of Medicine, Washington, DC.
Haramati
A
A
Roberts
C T
CT
LeRoith
D
D
D000375:Aging / Q000378:metabolism*; D000818:Animals; D005091:Exons; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D009392:Nephrectomy / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I