Effect of fetal nephrectomy on insulin-like growth factors and their binding proteins in sheep.
Bilateral nephrectomy retards fetal growth and decreases somatomedin (insulin-like growth factor-I, IGF-I) activity. To determine whether nephrectomy alters the synthesis of IGF-I or its binding proteins (IGFBPs), we studied 6 sets of twin fetuses. Kidneys were removed bilaterally from 1 twin of each set at 112-122 days of gestation (term 145 days). Plasma IGF-I concentrations were greater in nephrectomized fetuses than in the intact twins during the 1st week (261 +/- 35 vs. 153 +/- 21 ng/ml, p < 0.02; mean +/- SE) but not the 2nd week after surgery. Nephrectomy increased the abundance of the IGFBPs to levels 2-3 times greater than those in intact twins. Fetal hepatic IGFBP1 mRNA levels increased in 4 of 6 nephrectomized fetuses, while those of IGF-I, IGF-II, IGFBP2 were unchanged. Nephrectomy markedly alters the abundance of IGF-I and IGFBPs in plasma probably through mechanisms unrelated to synthesis.
Iwamoto
H S
HS
Children's Hospital Research Foundation, University of Cincinnati, Ohio, USA.
McConnell
C J
CJ
D000818:Animals; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005317:Fetal Growth Retardation / Q000209:etiology; D005333:Fetus / Q000601:surgery*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D009392:Nephrectomy / Q000009:adverse effects; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D012756:Sheep; D014427:Twins
D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II