Exogenous GH infusion to late-gestational fetal sheep does not alter fetal growth and metabolism.
The role of GH in the regulation of fetal growth and metabolism in late gestation is not well defined. The aim of this study was to determine the effects of exogenous GH infusion on fetal growth and feto-placental metabolism in the normally growing late-gestation fetal sheep. Eleven fetuses received pulsatile GH infusion (3.5 mg/day) for 10 days while 12 control fetuses received vehicle. The GH infusion was given as a continuous infusion (2.5 mg/day) plus an additional pulsatile component (30 pulses equivalent to 1 mg/day) designed to mimic the natural pattern of GH secretion. Fetal GH infusion raised the circulating fetal concentrations of GH threefold, but did not change fetal concentrations of IGF-I, IGF-binding protein-3, insulin or ovine placental lactogen. GH-treated fetuses had blood urea concentrations 15% lower than controls (P<0.05) and glucose uptake 18% lower per kg fetal weig! ht (P=0.06). There were no other differences attributable to fetal GH infusion in feto-placental metabolism, placental function or placental blood flow. GH-treated fetuses were larger than controls at postmortem (weight+13%, P<0.01; girth+5%, P<0.01; crown-rump length+3%, P<0.05). However, there were no differences between groups in measures of fetal growth (increment in chest girth and hindlimb length). GH-treated fetuses had heavier mothers and when maternal weight was included as a covariate in the analysis, there was no significant difference between treatment groups that could be attributed to GH treatment. GH infusion to normal fetal sheep does not appear to have a significant effect on feto-placental metabolism or fetal growth.
Bauer
M K
MK
Research Centre for Developmental Medicine and Biology, School of Medicine, Private Bag 92019, Auckland, New Zealand.
Harding
J E
JE
Breier
B H
BH
Gluckman
P D
PD
D000818:Animals; D002417:Cattle; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D005947:Glucose / Q000378:metabolism; D013006:Growth Hormone / Q000494:pharmacology*; D007328:Insulin / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D010920:Placenta / Q000378:metabolism; D010928:Placental Lactogen / Q000097:blood; D011247:Pregnancy; D012044:Regression Analysis; D012756:Sheep; D014508:Urea / Q000097:blood
D007328:Insulin; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D014508:Urea; D013006:Growth Hormone; D010928:Placental Lactogen; D005947:Glucose