Alsat E, Marcotty C, Gabriel R, Igout A, Frankenne F, Hennen G, Evain-Brion D
INSERM U427, Ecole Normale Supérieure, Paris, France.
Reprod Fertil Dev. 1995;7(6):1457-64. doi: 10.1071/rd9951457.
Consideration of the abnormal regulation of fetal growth leading to intrauterine growth retardation must take account of the fundamental differences between the regulation of growth before and after birth. The significance of endocrine regulators of growth differs greatly in utero. During the first trimester of pregnancy, embryonic growth might be controlled at the level of the individual organs by nutrient supply and by locally active growth factors. Later, fetal growth depends essentially upon materno-placental cooperation in delivering nutrients to the fetus. Therefore the major role of hormones in fetal growth is to mediate utilization of available substrate. Fetal growth seems to be regulated by fetal insulin, IGF-1 and certainly IGF-2, while growth hormone has only a secondary role to play. In late gestation, placental size and fetal growth rate are well correlated, pointing to a key role of the placenta in the regulation of fetal growth. It is therefore of importance to understand the molecular mechanisms involved in regulating placental development and endocrine functions. TGF alpha and EGF might play a major role as suggested by the modulation of their receptors with placental development, and by the specific alterations of epidermal growth factor receptors in intrauterine growth retardation. In addition, human placenta secretes specifically placental growth hormone. The concentration of placental growth hormone is significantly decreased in sera of pregnant women bearing a fetus with intrauterine growth retardation.
在考虑导致胎儿生长受限的胎儿生长异常调节时，必须考虑出生前后生长调节的根本差异。生长的内分泌调节因子在子宫内的意义有很大不同。在妊娠的前三个月，胚胎生长可能在个体器官水平上由营养供应和局部活性生长因子控制。后来，胎儿生长主要依赖于母体与胎盘在向胎儿输送营养方面的合作。因此，激素在胎儿生长中的主要作用是介导可用底物的利用。胎儿生长似乎受胎儿胰岛素、IGF-1以及肯定还有IGF-2的调节，而生长激素只起次要作用。在妊娠后期，胎盘大小与胎儿生长速度密切相关，表明胎盘在胎儿生长调节中起关键作用。因此，了解调节胎盘发育和内分泌功能的分子机制很重要。TGFα和EGF可能起主要作用，这是由它们的受体随胎盘发育的调节以及子宫内生长受限中表皮生长因子受体的特异性改变所表明的。此外，人胎盘特异性分泌胎盘生长激素。怀有宫内生长受限胎儿的孕妇血清中胎盘生长激素的浓度显著降低。
