Anthony R V, Pratt S L, Liang R, Holland M D
Department of Physiology, Colorado State University, Fort Collins 80523, USA.
J Anim Sci. 1995 Jun;73(6):1861-71. doi: 10.2527/1995.7361861x.
The placenta plays a critical role in providing an environment that supports optimal fetal growth. It does this by providing the site of nutrient transfer from the mother to the fetus and waste secretion from the fetus to the mother, acting as a barrier against pathogens and the maternal immune system, and as an active endocrine organ capable of secreting hormones, growth factors, cytokines, and other bioactive products. Among the hormones produced by the placenta are members of the growth hormone/prolactin gene family, the placental lactogens (PL) and prolactin-related proteins. Although the exact functions of the placental members of this gene family have not been entirely elucidated, the available evidence supports a role for some in modulating maternal and fetal metabolism. The PL are secreted into the maternal and fetal circulations and, at least in ruminants, seem to mediate their effects through unique receptors, although this remains controversial. One action of the PL may be to modulate fetal IGF production. Research with mice, using gene ablation techniques, indicates the importance of the IGF for maintaining normal fetal growth rate. This research provided data on the timing of the onset of IGF effects on fetal growth and the receptors through which these effects are mediated. This review is about the structure, mechanism of action, and potential function of the placental members of the growth hormone/prolactin gene family and the recent evidence on the role of IGF in fetal growth regulation.
胎盘在提供支持胎儿最佳生长的环境方面发挥着关键作用。它通过提供母亲与胎儿之间营养物质转移以及胎儿向母亲排泄废物的场所来实现这一点，充当抵御病原体和母体免疫系统的屏障，并且作为一个能够分泌激素、生长因子、细胞因子和其他生物活性产物的活跃内分泌器官。胎盘产生的激素包括生长激素/催乳素基因家族的成员、胎盘催乳素（PL）和催乳素相关蛋白。尽管该基因家族中胎盘成员的确切功能尚未完全阐明，但现有证据支持其中一些成员在调节母体和胎儿代谢方面发挥作用。PL分泌到母体和胎儿循环中，至少在反刍动物中，似乎通过独特的受体介导其作用，尽管这仍存在争议。PL的一个作用可能是调节胎儿IGF的产生。利用基因敲除技术对小鼠进行的研究表明IGF对于维持正常胎儿生长速度的重要性。这项研究提供了关于IGF对胎儿生长影响开始的时间以及介导这些影响的受体的数据。本综述围绕生长激素/催乳素基因家族胎盘成员的结构、作用机制和潜在功能，以及近期关于IGF在胎儿生长调节中作用的证据展开。
