Signals that link energy to reproduction: gastric fill, bulk intake, or caloric intake?
Signals that link energy to reproduction: gastric fill, bulk intake, or caloric intake?
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将能量与生殖联系起来的信号：胃填充、大量摄入或热量摄入？
DOI：
10.1016/j.physbeh.2008.12.005
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发表时间：
2009
影响因子：
2.9
通讯作者：
Schneider,JillE
中科院分区：
文献类型：
--
作者：
Szymanski,LauraA;Tabaac,BurtonJ;Schneider,JillE
生殖过程受到代谢燃料供应不足的抑制，这种抑制增加了在能量挑战期间存活的机会，并通过推迟耗费能量的过程直到燃料可用来优化生殖成功。将能量供应与繁殖联系起来的机制尚不清楚，因此，在这项研究中，我们测试了这样一种假设，即发情周期对来自大量摄入和胃填充的感觉信号最敏感，而不是来自热量摄入或细胞内可氧化燃料的信号。标准实验室饲料的卡路里含量被稀释25%、50%或75%，并在整个发情周期的第二天喂给缺乏食物的雌性仓鼠(排卵和发情行为通常发生在第四天)。大容量摄入量/胃填充假说不被支持，因为大容量摄入量随着饲料的稀释而增加，而表现出正常的4天发情周期的仓鼠的频率随着饲料的稀释而减少，同时热量摄入量和血浆胰岛素浓度也减少。胃排空率随饲料稀释度的变化不明显。尽管食用稀释日粮显著延长了发情周期，但它并不影响怀孕的发生率、产仔数或幼崽体重。因此，当仓鼠摄入足够的能量来支持发情行为时，它们就完全恢复了繁殖潜力。总而言之，无论是大量摄入还是胃充盈，都不能提供生殖所必需的关键信号，这与生殖主要是有反应的燃料供应的想法是一致的。
Reproductive processes are inhibited by deficits in the availability of metabolic fuels, and this inhibition increases the chances of survival during energetic challenges and optimizes reproductive success by delaying energetically costly processes until fuels become available. The mechanisms that link energy availability to reproduction are unknown, and thus, in this study we tested the hypothesis that estrous cycles are most sensitive to sensory signals from bulk intake and gastric fill as opposed to signals from caloric intake or the availability of intracellular oxidizable fuels. The caloric content of a standard laboratory chow diet was diluted by 25, 50, or 75% with the largely indigestible fiber, cellulose, and fed to food-deprived, female hamsters throughout day 2 of the estrous cycle (ovulation and estrous behavior normally occur on day 4). The bulk intake/gastric fill hypothesis was not supported because bulk intake increased the more the diet was diluted, whereas the frequency of hamsters showing normal 4-day estrous cycles decreased with diet dilution, along with decreases in caloric intake and in plasma insulin concentrations. Rate of gastric emptying did not change significantly with diet dilution. Although consumption of a diluted diet significantly lengthened the estrous cycle, it did not affect incidence of pregnancy, litter size or pup weight. Thus, when hamsters ingest sufficient energy to support estrous behavior, they fully recover reproductive potential. In summary, neither bulk intake nor gastric fill provides critical signals necessary for reproduction, consistent with the idea that reproduction is primarily responsive fuel availability.