Effects of maternal protein malnutrition on fetal growth, plasma insulin-like growth factors, insulin-like growth factor binding proteins, and liver insulin-like growth factor gene expression in the rat.
We examined the effects of maternal dietary protein restriction on fetal growth and expression of IGF-I and -II, and IGF-binding proteins (IGFBP). We sought to dissociate the respective effects of maternal protein versus calorie restriction on growth indices and IGF synthesis by the neonates of protein-restricted dams. Pregnant Wistar rats (six to eight per group) fed a low (5%) protein diet throughout gestation had impaired body weight gain compared with controls fed a normal (20%) protein diet (by 45%, p < 0.001). Their serum and liver IGF-I concentrations and liver IGF-I mRNA concentrations were also reduced by 60, 80, and 50%, respectively. Serum IGFBP-3 was reduced by 60% in protein-restricted dams within 1 to 2 h after delivery (p < 0.001 versus controls), although IGFBP-1, -2, and -4 were not significantly affected by the dietary protein intake. In pups of protein-restricted dams, the mean body and liver weight at birth was 15-20% less than that observed in the progeny from normal protein-fed dams (p < 0.01). Their plasma and liver IGF-I concentrations were 30 and 60% lower, respectively, whereas liver IGF-I mRNA abundance was reduced by 50% (p < 0.01). In contrast, neonatal plasma IGF-II and liver IGF-II mRNA concentrations were not significantly affected by the maternal protein malnutrition. Also, the plasma levels of IGFBP were not altered in the growth-retarded pups. Maternal protein restriction did not affect fetal and placental growth, plasma and liver IGF-I levels, and liver IGF-I mRNA abundance in 20-d-old fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)
Muaku
S M
SM
Unité de Diabétologie et Nutrition, University of Louvain School of Medicine, Brussels, Belgium.
Beauloye
V
V
Thissen
J P
JP
Underwood
L E
LE
Ketelslegers
J M
JM
Maiter
D
D
D000818:Animals; D000831:Animals, Newborn; D002352:Carrier Proteins / Q000378:metabolism*; D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005865:Gestational Age; D018969:Insulin-Like Growth Factor Binding Proteins; D008099:Liver / Q000378:metabolism; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011502:Protein-Energy Malnutrition / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D013002:Somatomedins / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins