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Growth hormone, insulin-like growth factor I, insulin and C-peptide during human fetal life: in-utero study
S Salardi1, L F Orsini, E Cacciari
1Department of Obstetrics and Gynaecology, University of Bologna, Italy.
Insights
Serum growth hormone (GH) and insulin levels are present in fetuses from 19 weeks gestation. However, these hormones do not appear to directly regulate fetal growth.
Area of Science:
- Endocrinology
- Fetal Medicine
- Reproductive Biology
Background:
- Fetal growth is influenced by complex hormonal regulation.
- Growth hormone (GH) and insulin are key metabolic and growth regulators in postnatal life.
- Understanding their role during fetal development is crucial.
Purpose of the Study:
- To measure serum levels of GH, insulin-like growth factor-I (IGF-I), insulin, and C-peptide in human fetuses.
- To investigate the developmental trends of these hormones between 19 and 37 weeks of gestation.
- To explore potential correlations between these hormones and fetal growth parameters.
Main Methods:
- Radioimmunoassay (RIA) was used to measure hormone concentrations.
- Fetal blood was collected in utero via umbilical cord puncture.
- Hormone levels were analyzed in relation to gestational age and femoral length.
Main Results:
- IGF-I levels were below the assay's detection limit.
- GH levels increased significantly from 19 to 25 weeks gestation.
- Insulin and C-peptide levels showed a significant increase from 19 to 37 weeks gestation.
- Higher GH levels were observed in fetuses with smaller femoral length (below 5th percentile).
- GH and insulin levels did not correlate with birth weight or maternal hormone levels.
Conclusions:
- Living human fetuses exhibit detectable levels of GH and insulin from 19 weeks gestation.
- Fetal GH and insulin levels increase with advancing gestation.
- These hormones do not appear to be the primary drivers of fetal growth in the studied period.
- Further research is needed to elucidate the precise roles of GH and insulin in fetal development.
Abstract:
Serum growth hormone (GH), insulin-like growth factor (IGF-I), insulin and C-peptide were measured by RIA in fetal blood collected in utero by umbilical cord puncture performed for a variety of indications. Eighty-four fetuses were aged 19-25 weeks and 14 were 26-37 weeks. IGF-I values were lower than the sensitivity of the method. The range for GH was 3-197 micrograms/l (GH-micrograms/l x 2 = mU/l), for insulin 14.3-117 pmol/l, for C-peptide 66.2-827.5 pmol/l. GH significantly increased from week 19 to 25; insulin and C-peptide levels increased from week 19 to 37. GH levels at 19-25 weeks were significantly higher in fetuses with femoral length less than the 5th compared with those with femoral length greater than the 95th centile for that age. GH and insulin levels did not correlate with weight at birth or with maternal hormone levels. These data provide evidence for a presence in living fetuses, from the 19th week, of high levels of GH and of insulin levels not very different from those in adults but these hormones do not seem to be directly responsible for fetal growth.