The effect of maternal starvation on plasma insulin-like growth factor I concentrations in the late gestation ovine fetus.
In view of the suggested relationship between substrate availability, fetal growth and circulating fetal IGF-I concentrations, we investigated the effect of maternal starvation on plasma IGF-I levels in the late gestation ovine fetus. Ten fetuses aged 125-130 d gestation were sampled daily from indwelling arterial catheters. Ewes were starved for 72 h. Starvation was terminated with an intravenous infusion of 10% glucose to the ewe. Food was then replaced 4 h later. Fetal IGF-I concentrations fell from 176.1 +/- 15.2 ng/mL before starvation to 124.5 +/- 10.3 ng/mL after 72 h starvation (p less than 0.05, n = 10). The fall in IGF-I concentrations was reversed by 4 h of maternal glucose infusion. In five fetuses, where samples were obtained 24 h after terminating the starvation, fetal IGF-I concentrations were comparable to those seen before starvation (180.0 +/- 37.7 ng/mL). This study demonstrates that acute maternal starvation causes a reversible decrease in fetal plasma IGF-I levels. These studies suggest that nutrient and in particular glucose availability is a significant determinant of fetal IGF-I secretion and support the hypothesis that IGF-I may play a role in the regulation of fetal growth.
Bassett
N S
NS
Paediatrics Department, School of Medicine, University of Auckland, New Zealand.
Oliver
M H
MH
Breier
B H
BH
Gluckman
P D
PD
D000818:Animals; D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005865:Gestational Age; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008431:Maternal-Fetal Exchange / Q000502:physiology*; D011247:Pregnancy; D012756:Sheep; D013002:Somatomedins / Q000378:metabolism*; D013217:Starvation / Q000097:blood*
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I