School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK.
Edinburgh Genomics, University of Edinburgh, Edinburgh, EH9 3FL, Scotland, UK.
J Comp Physiol B. 2023 Mar;193(2):171-192. doi: 10.1007/s00360-023-01474-9. Epub 2023 Jan 18.
Peak lactation occurs when milk production is at its highest. The factors limiting peak lactation performance have been subject of intense debate. Milk production at peak lactation appears limited by the capacity of lactating females to dissipate body heat generated as a by-product of processing food and producing milk. As a result, manipulations that enhance capacity to dissipate body heat (such as fur removal) increase peak milk production. We investigated the potential correlates of shaving-induced increases in peak milk production in laboratory mice. By transcriptomic profiling of the mammary gland, we searched for the mechanisms underlying experimentally increased milk production and its consequences for mother-young conflict over weaning, manifested by advanced or delayed involution of mammary gland. We demonstrated that shaving-induced increases in milk production were paradoxically linked to reduced expression of some milk synthesis-related genes. Moreover, the mammary glands of shaved mice had a gene expression profile indicative of earlier involution relative to unshaved mice. Once provided with enhanced capacity to dissipate body heat, shaved mice were likely to rear their young to independence faster than unshaved mothers.
泌乳高峰期是指产奶量最高的时候。限制泌乳高峰期性能的因素一直是激烈争论的话题。泌乳高峰期的产奶量似乎受到泌乳雌性动物消耗因处理食物和产奶而产生的体热的能力的限制。因此，增强散热能力的操作（如去除毛发）会增加产奶量的峰值。我们研究了剃毛引起的实验室小鼠产奶量峰值增加的潜在相关性。通过对乳腺的转录组分析，我们寻找了实验性增加产奶量的机制及其对母婴在断奶问题上冲突的影响，表现为乳腺的提前或延迟退化。我们证明，剃毛引起的产奶量增加与一些与牛奶合成相关的基因表达减少有关。此外，与未剃毛的小鼠相比，剃毛小鼠的乳腺具有更早退化的基因表达谱。一旦提供了增强的散热能力，剃毛的小鼠就有可能比未剃毛的母亲更快地将幼崽抚养成独立的个体。
