Arch Dis Child Fetal Neonatal Ed 1997;77:F100-F104 ( September )
Developmental pattern of fetal growth hormone, insulin-like
growth factor I, growth hormone binding protein and insulin-like growth
factor binding protein-3
P Pirazzoli,a
E Cacciari,a
R De Iasio,a
M C Pittalis,b
P Dallacasa,a
S Zucchini,a
S Gualandi,a
S Salardi,a
C David,b
S Boschic
a Department of Paediatrics, Central Laboratory St Orsola
Hospital, University of Bologna, b Prenatal Pathophysiology Unit
Institute of Obstetrics and Gynaecology, University of
Bologna, c Clinical Pharmacology Unit, University of Bologna
Correspondence to: Professor
Emanuele Cacciari, 1st Paediatric Clinic, via Massarenti 11, 40138 Bologna, Italy.
Accepted 9 April
1997
AIMS
To evaluate the developmental pattern of
fetal growth hormone (GH), insulin-like growth factor I (IGF-I), GH
binding protein (GHBP) and IGF binding protein-3 (IGF-3); to determine
the implications for fetal growth.
METHODS
Serum GH, IGF-I, GHBP and IGFBP-3 were
measured in 53 fetuses, 41 aged 20-26 weeks (group A) and 12 aged
31-38 weeks (group B). Fetal blood samples were obtained by direct
puncture of the umbilical vein in utero. Fetal blood samples were taken
to rule out
thalassaemia, chromosome alterations, mother to fetus
transmissible infections, and for maternal rhesus factor. GHBP was
determined by gel filtration chromatography of serum incubated
overnight with 125I-GH. GH, IGF-I and IGFBP-3 were
determined by radioimmunoassay.
RESULTS
Fetal serum GH concentrations in group A
(median 29 µg/l, range 11-92) were significantly higher (P<0.01)
than those of group B (median 16.7 µg/l, range 4.5-29). IGF-I in
group A (median 20 µg/l, range 4.1-53.3) was significantly lower
(P<0.01) than in group B (median 75.2 µg/l, range 27.8-122.3).
Similarly, IGFBP-3 concentrations in group A (median 950 µg/l, range
580-1260) were significantly lower than those of group B (median 1920 µg/l, range 1070-1770). There was no significant difference between
GHBP values in group A (median 8.6%, range 6.6-12.6) and group B
(median 8.3%, range 6-14.3). Gestational age correlated positively
with IGF-I concentrations (P<0.0001) and IGFBP-3 (P<0.0001) and
negatively with GH (P<0.0001). GHBP values did not correlate with
gestational age. Multiple regression analysis showed a negative
correlation between GH:IGF-I ratio and fetal growth indices
CONCLUSIONS
The simultaneous evaluation of fetal
GH, IGF-I, IGFBP-3 and GHBP suggests that the GH-IGF-I axis might
already be functional in utero. The progressive
improvement in the efficiency of this axis in the last part of
gestation does not seem to be due to an increase in GH receptors.
Keywords:
insulin-like growth factor I;
IGF-binding protein;
growth hormone-binding protein;
somatotropin
© 1997 by Archives of Disease in Childhood