The concentration of insulin-like growth factor-I and insulin-like growth factor-binding protein-1 in human umbilical cord serum at delivery: relation to fetal weight.
Serum levels of insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-1 (IGFBP-1) have been determined by radioimmunoassay in the maternal circulation (n = 91) and in the umbilical artery (n = 56) and vein (n = 90) of man. In both the umbilical artery and vein, the concentration of serum IGF-I showed an inverse correlation with birthweight (P less than 0.005 and P less than 0.001 respectively); the mean serum IGF-I levels in the small-for-gestational-age (SGA) group were significantly higher than those in average-for-gestational-age (AGA) neonates (P less than 0.01 and P less than 0.001 respectively). However, maternal serum IGF-I showed no association with birthweight and there was no significant difference between the SGA and AGA groups. These observations imply that the production of IGF-I in the maternal and fetal compartments is independent and that there is unlikely to be transfer of IGF-I across the placenta. Serum IGFBP-1 levels in both maternal and umbilical cord blood (artery and vein) showed an inverse relation to birthweight (P less than 0.001, P less than 0.005 and P less than 0.001 respectively). Increased IGFBP-1 levels in the umbilical artery and vein were observed in the SGA group. These findings suggest that IGFBP-1 might inhibit the action of IGF-I in both the maternal and the fetal compartments and that the rise in IGFBP-1 could be a primary factor in retardation of fetal growth. Alternatively, circulating IGF-I and IGFBP-1 levels may only be a secondary reflection of local tissue events involved in fetal growth.
Wang
H S
HS
Department of Obstetrics, Gynaecology and Reproductive Physiology, St Bartholomew's Hospital Medical College, West Smithfield, London.
Lim
J
J
English
J
J
Irvine
L
L
Chard
T
T
D001724:Birth Weight; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D011247:Pregnancy; D011863:Radioimmunoassay
D007334:Insulin-Like Growth Factor I