Circulating levels of growth hormone, insulin-like growth factor-I and prolactin in normal, growth retarded and anencephalic human fetuses

Abstract

We measured growth hormone (GH), insulin-like growth factor-I (IGF-I), and both total and glycosylated prolactin (PRL) levels in 131 blood samples obtained by cordocentesis in normal and abnormal fetuses from 19 to 40 weeks of gestation. In normal fetuses, IGF-I and PRL levels showed a positive correlation and GH a negative correlation with gestational age. A negative relation between GH and IGF-I levels was observed, while PRL did not show any correlation with both GH and IGF-I concentrations. IGF-I increased from 5.6 +/- 3 (at 19-22 weeks) to 10.7 +/- 5 nmol/l at term; GH decreased from 31 +/- 10 to 7.7 +/- 4 micrograms/l and PRL increased from 16 +/- 18 to 139 +/- 76 micrograms/l. Glycosylated PRL accounted for about 15% of total PRL, a value similar to that found in normal adults. In 27 fetuses of 27-37 weeks with intra-uterine growth retardation, GH and PRL levels were higher and IGF-I levels lower than in normal fetuses matched for week of gestation. In 8 anencephalic fetuses of 19-26 weeks of gestation, both GH and IGF-I levels were lower, and PRL levels were higher than in matched controls. Altogether these data support the views that a) both GH and PRL secretion are under the hypothalamic control during fetal development, b) the serum GH decrease from midgestation to the end of pregnancy is mediated by the negative feed-back mechanism of increasing IGF-I levels and c) IGF-I production is mainly regulated by fuel supply and only partially by GH.

Growth Hormone, Insulin-Like Growth Factor-I and Insulin-Like Growth Factor Binding Protein-3 Are Regulated Differently in Small-for-Gestational-Age and Appropriate-for-Gestational-Age Neonates

“…In contrast to the report of Arosio et al [20] we found no correlation between GH levels and IGF-I levels. These discrepancies could stem from the pulsatile nature and the very high level of GH secretion in the neonate, with marked changes in GH levels [16].…”

Circulating levels of ghrelin in human fetuses

“…First, this pattern of secretion may be an additional component of the altered somatotrophic axis observed in growthrestricted fetuses. Indeed, as previously described, plasma GH levels in cord blood were higher in IUGR fetuses than in normal fetuses and negatively correlated with birth weight, probably as a result of the reduced IGF-I levels present in this pathological condition (22,23). Therefore, it is likely that low IGF-I associated with intrauterine growth restriction may induce ghrelin overproduction, although the feedback mechanisms regulating ghrelin secretion are still poorly understood.…”

The Role of Maternal Factors, Postnatal Nutrition, Weight Gain, and Gender in Regulation of Serum IGF-I among Preterm Infants

“…Results from measurements of IGF-I in serum of fetuses and preterm or term newborn infants have been more variable, as some groups find no difference in serum IGF-I concentrations between the male and female gender (6,10,13,15) and others report higher IGF-I in girls than boys (41,42). Reasons for this gender difference are not clear, but it has been suggested that differences in sex steroids could influence the secretion of IGF-I in utero (43).…”

“…Receptors for IGF-I are found in various tissues early in gestation (3), and fetal tissues seem to have enhanced sensitivity to IGF-I compared with later in life (4). Using cordocenteses, it has been possible to determine the "normal" range of IGF-I in fetal serum and to define a positive correlation between serum concentration of IGF-I and gestational age (5)(6)(7)(8)(9)(10). IGF-I levels are similar in arterial and venous cord serum, suggesting a fetal origin (1).…”