Growth Hormone and Growth Factors during Perinatal Life

Abstract

Pituitary growth hormone (GH) is present in early pregnancy in the fetal circulation. The concentrations are higher than ever found during life, due to an unrestrained, basal secretion. GH receptors develop around midpregnancy, when they are present in low concentrations, and there is a rapid increase during the first months of life. The function of fetal GH – characterized by a nearly complete GH resistance – is largely unclear: there is only a small effect on longitudinal growth, and the regulation of growth factors is independent of GH. Possibly, metabolic effects of GH on fat and glucose metabolism and body composition are of greater importance. During the first months of life, the rapid fetal (GH-independent, nutrition-dependent) growth decelerates, a process that is partly compensated by the onset of GH-dependent longitudinal growth.

Ghrelin Expression in Human and Rat Fetal Lungs and the Effect of Ghrelin Administration in Nitrofen-Induced Congenital Diaphragmatic Hernia

“…Nevertheless, the possibility of involvement of GH-dependent endocrine pathways cannot be ruled out. In fact, ghrelin expression in fetal lung reaches its peak at mid-gestation, when serum GH levels also reach maximal values (22). The presence of GH mRNA in the fetal rat lung during pseudoglandular stage, was recently documented (23), and it has been suggested that fetal GH can interact with GH receptors existent in fetal lung epithelium (24,25) and modulate lung growth by interfering with IGF activity while increasing IGFBP-2 (26).…”

Effect of xylazine, isoxsuprine, and lidocaine on Doppler sonographic uterine and umbilical blood flow measurements in cows during the last month of pregnancy

“…Likewise, there was no decrease in RI in cows from week 37 to week 39 of gestation [38]. The fall in RI represents an adaption to growing demands on gas exchange and transfer of nutrients and metabolites during the last trimester of gestation [36][37][38]. Structural changes in blood vessels of the human fetoplacental unit are associated with increased vascular elasticity and result in a reduction of vascular resistance [39].…”

“…A continuous decrease of 35% in the RI of both AUT occurred in cattle during the first 28 weeks of gestation, but no further decrease was noted at monthly measurements during the remainder of gestation [6]. Likewise, there was no decrease in RI in cows from week 37 to week 39 of gestation [38]. The fall in RI represents an adaption to growing demands on gas exchange and transfer of nutrients and metabolites during the last trimester of gestation [36][37][38].…”

Early postnatal alteration of body composition in preterm and small-for-gestational-age infants: implications of catch-up fat

“…Previous studies have shown that IGF-I has a more critical role than the other factors (56)(57)(58), and growth hormone is not an important regulator of IGF-I secretion during perinatal life (57,58). In addition, children with IGF-I gene deletion are characterized by severe prenatal and postnatal growth retardation (59).…”