A. Varvarigou et al., GROWTH-HORMONE, INSULIN-LIKE GROWTH-FACTOR-I AND PROLACTIN IN SMALL-FOR-GESTATIONAL-AGE NEONATES, Biology of the neonate, 65(2), 1994, pp. 94-102
Growth hormone (hGH), insulin-like growth factor-I (IGF-I) and prolact
in (PRL) were measured in the cord and venous blood of small for gesta
tional age (SGA) neonates in order to evaluate their endocrine status
during the first 3 days of life. Although there were SGA newborns with
both high and normal levels of hGH, the mean (+/- SD) concentration o
f hGH in the cord blood of the SGA neonates was 72.1 +/- 50.6 ng/ml, w
hereas in the appropriate for gestational age (AGA) newborns it was 37
.0 +/- 23.5 (p = 0.001). The IGF-I in the cord blood of the SGA and th
e AGA newborns was 194.2 +/- 174.8 ng/ml and 77.3 +/- 50.2, respective
ly (p = 0.013). The PRL in the SGA and AGA newborns was 184.8 +/- 62.4
ng/ml and 126.8 +/- 60.5, respectively (p = 0.0005). On the 3rd day t
he hGH in the SGA babies was 50.7 +/- 41.2, whereas in the AGA it was
24.3 +/- 12.3 (p = 0.034). On the same day the IGF-I was 133.9 +/- 120
.9 and 44.8 +/- 31.6, respectively (p > 0.05). Similarly, the PRL was
157.1 +/- 52.3 and 90.9 +/- 52.5, respectively (p = 0.0008). All neona
tes with high hGH concentrations had low IGF-I levels, whereas of thos
e with normal hGH half had high and half normal IGF-I levels. There wa
s no difference in the hormone levels between symmetric and asymmetric
intrauterine growth-retarded infants. The findings suggest that the S
GA neonates are heterogeneous comprising three groups. The neonates wi
th high hGH and low IGF-I may have resistance at the level of the hGH
receptor or a defect in IGF-I synthesis, whereas those with normal hGH
and high IGF-I may have a post-IGF-I receptor defect, with compensato
ry increase in IGF-I synthesis independent of hGH control.