Atrophy or hypertrophy in chronic renal ischemia: role of the IGF-I system.
To examine the role of insulin-like growth factor-1 (IGF-1) in renal atrophy of rats with two-kidney, one-clip (2K1C), in which the clipped kidney atrophies, and in the one-kidney, one-clip (IK1C) model of renovascular hypertension, in which it hypertrophies, we studied levels of IGF-I, mRNA, and protein in 2K1C, IK1C, and unilateral nephrectomy (NPX) in rats by solution-hybridization RNase protection, and radioimmunoassay, respectively, both cross-reactively and longitudinally at 3, 10, and 30 days after clipping. Three days after clipping, there were no differences in blood pressure or kidney size; however, 10 and 30 days postoperation, the clipped kidney shrank in the 2K1C model. The nonclipped 2K1C and the clipped lK1C and unilateral nephrectomy kidneys increased in weight (P < .05. At day 3 the IGF-I levels were lower (557 +/- 54, 335 +/- 61 ng/g in control and clipped 2K1C, P < .05, v 1,074 +/- 186, 1,109 +/- 54, and 1,154 +/- 200 ng/g kidney, nonclipped 2K1C, 1K1C, and NPX, respectively). At 30 days the IGF-I levels were 300 +/- 24 ng/g in control (P < .05) v clipped 2K1C, 160 +/- 19, 218 +/- 20 ng/g in nonclipped 2K1C and 406 +/- 33 and 470 +/- 34 ng/g in 1K1C and NPX, respectively (P < .05) v control and clipped 2K1C. Kidney mRNA was increased in the clipped 2K1C. In conclusion, the kidney that had higher IGF-I levels early in nonclipped 2K1C, 1K1C, and nephrectomy hypertrophied, and the kidney (clipped 2K1C) that failed to increase IGF-I atrophied. IGF-I levels are dissociated from the local mRNA message.
Bursztyn
M
M
Department of Medicine, Hadassah University Hospital, Mount Scopus, Jerusalem, Israel. bursz@cc.huji.ac.il
Flyvbjerg
A
A
Weiss
O
O
Mekler
J
J
Raz
I
I
D000818:Animals; D001284:Atrophy; D002908:Chronic Disease; D006977:Hypertension, Renal / Q000473:pathology* / Q000503:physiopathology; D006984:Hypertrophy; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000032:analysis / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000235:genetics*; D007511:Ischemia / Q000473:pathology* / Q000503:physiopathology; D007668:Kidney / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D008297:Male; D009392:Nephrectomy; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000235:genetics; D012079:Renal Circulation; D012260:Ribonucleases
D018970:Insulin-Like Growth Factor Binding Protein 1; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D012260:Ribonucleases