French Susannah S, Greives Timothy J, Zysling Devin A, Chester Emily M, Demas Gregory E
Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA.
Proc Biol Sci. 2009 Nov 22;276(1675):4003-11. doi: 10.1098/rspb.2009.1199. Epub 2009 Aug 26.
The primary goal of virtually all organisms is to produce genetic offspring, thereby passing on their genes to future generations. Offspring production, however, is limited by available resources within an environment. Moreover, distributing sufficient energy among competing physiological systems is challenging and can result in trade-offs between self-maintenance and offspring investment when resources are limited. In the current study, we tested the hypothesis that the adipose hormone leptin is involved in mediating energetic trade-offs between competing physiological systems. Specifically, we tested the effects of elevated maternal leptin on investment into offspring production versus self maintenance (immune function), in the Siberian hamster (Phodopus sungorus). The current study provides the first evidence that leptin serves as a signal to mothers of available energy resulting in epigenetic effects. Therefore, elevated leptin allows females to retain more embryos to parturition, and rear more offspring to weaning via reduced maternal infanticide. Innate immune response was suppressed seemingly as a result of these enlarged litters, suggesting that the observed fitness increase is not without costs to the mother. Collectively, these findings suggest that leptin plays a critical role in allowing mothers to determine how much energy to invest in the production and care of young versus self-maintenance.
几乎所有生物体的主要目标都是产生有遗传特性的后代，从而将它们的基因传递给后代。然而，后代的产生受到环境中可用资源的限制。此外，在相互竞争的生理系统之间分配足够的能量具有挑战性，并且当资源有限时，可能会导致自我维持和后代投资之间的权衡。在当前的研究中，我们检验了脂肪激素瘦素参与介导相互竞争的生理系统之间能量权衡的假设。具体而言，我们在西伯利亚仓鼠（Phodopus sungorus）中测试了母体瘦素升高对后代生产投资与自我维持（免疫功能）的影响。当前的研究提供了首个证据，即瘦素作为一种向母亲传递可用能量的信号，会产生表观遗传效应。因此，瘦素升高使雌性能够保留更多胚胎直至分娩，并通过减少母体杀婴行为养育更多后代直至断奶。由于这些窝仔数量增加，先天性免疫反应似乎受到了抑制，这表明观察到的适应性增加对母亲来说并非没有代价。总的来说，这些发现表明瘦素在使母亲能够决定在养育幼崽与自我维持方面投入多少能量方面起着关键作用。
