School of Zoology, Private Bag 05, University of Tasmania, Hobart, Tasmania, 7001, Australia.
Comp Biochem Physiol A Mol Integr Physiol. 2011 Oct;160(2):184-9. doi: 10.1016/j.cbpa.2011.05.028. Epub 2011 Jun 2.
In mammals, there is experimental evidence that circulating maternal cortisol is transferred to the embryos across the placenta during gestation. Direct effects of this maternal cortisol may allow embryos to display phenotypic plasticity to cope with postnatal environments (i.e., pre-programming). The potential for maternal hormone induced-adaptation may be of considerable evolutionary significance in viviparous animals. However, to date, there is no such direct evidence that circulating maternal corticosterone passes through the placenta and into the embryos of viviparous reptiles. In this study, we assessed the transfer of (3)H-corticosterone injected into females of the lizard Pseudemoia entrecasteauxii into maternal blood, maternal liver, the embryo, the yolk and the amniotic fluid during mid-to-late gestation. We provide direct evidence that circulating maternal corticosterone passes through the placenta into the embryos in this species. Transfer of maternal corticosterone into the embryos significantly decreased at the end of embryonic development. We discuss these results in terms of the relationships between the degree of corticosterone transfer and embryonic stage. These results demonstrate the potential for direct effects of maternal corticosterone, including endocrine pre-programming, upon the developing embryos in viviparous lizards.
在哺乳动物中，有实验证据表明，母体循环中的皮质醇在妊娠期间通过胎盘转移到胚胎中。这种母体皮质醇的直接作用可能使胚胎能够表现出表型可塑性，以应对产后环境（即预编程）。母体激素诱导适应的潜力在胎生动物中可能具有相当重要的进化意义。然而，迄今为止，尚无直接证据表明循环母体皮质酮穿过胎盘进入胎生爬行动物的胚胎中。在这项研究中，我们评估了（3）H-皮质酮注入到 Pseudemoia entrecasteauxii 蜥蜴的雌性体内后，在妊娠中期到晚期转移到母体血液、母体肝脏、胚胎、蛋黄和羊水的情况。我们提供了直接证据表明，在该物种中，循环母体皮质醇穿过胎盘进入胚胎。在胚胎发育末期，母体皮质醇向胚胎的转移明显减少。我们根据皮质醇转移的程度与胚胎阶段之间的关系讨论了这些结果。这些结果表明，母体皮质醇可能对胎生蜥蜴的发育中的胚胎产生直接影响，包括内分泌预编程。
