Chronic but not acute energy restriction increases intestinal nutrient transport in mice
Chronic but not acute energy restriction increases intestinal nutrient transport in mice
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DOI：
10.1093/jn/131.3.779
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发表时间：
2001-03-01
影响因子：
4.2
通讯作者：
Prabhakaram, S
中科院分区：
文献类型：
--
作者：
Ferraris, RP;Cao, QX;Prabhakaram, S
慢性能量限制（ER）显著增强老年小鼠肠道对营养物质的吸收。营养吸收的适应性变化是只在延长的内质网后发生还是在内质网启动后立即发生？为了确定适应的时间过程，我们测量了3月龄小鼠在开始ER（70%自由采食）后1-270天的肠道葡萄糖、果糖和脯氨酸转运率。相同年龄的小鼠随意进食（AL）作为对照组;第三组仅饥饿1或2天，以区分急性ER和饥饿的影响。1、2、10 d急性ER对养分吸收无影响。饥饿显著降低了每厘米肠质量，从而降低了每厘米转运量和肠吸收能力，而没有显著改变每毫克肠的转运量。ER为24天只增加果糖的吸收，而ER为270天提高了20- 100%的所有营养素的吸收。尽管体重存在显著差异，但AL和ER小鼠的胃、小肠、盲肠和大肠湿重通常相似，表明胃肠道在ER期间得以保留。相比之下，ER和AL小鼠之间的肺、肾、脾、心脏、胰腺和肝脏的湿重各相差40-120%。肠转运适应性在ER过程中逐渐发展，这些适应性的主要机制是每毫克组织的转运活性急剧增加。
Chronic energy restriction (ER) dramatically enhances intestinal absorption of nutrients by aged mice. Do adaptations in nutrient absorption develop only after extended ER or immediately after its initiation? To determine the time course of adaptations, we measured rates of intestinal glucose, fructose and proline transport 1-270 d after initiation of ER (70% of ad libitum) in 3-mo old mice. Mice of the same age that consumed food ad libitum (AL) sewed as controls; a third group was starved for 1 or 2 d only, to distinguish the effects of acute ER from those of starvation. Acute ER of 1, 2 and 10 d had no effect on nutrient absorption. Starvation significantly decreased intestinal mass per centimeter, thereby reducing transport per centimeter and intestinal absorptive capacity without significantly altering transport per milligram of intestine. ER for 24 d enhanced only fructose uptake, whereas ER for 270 d enhanced uptake of all nutrients by 20-100%. Despite marked differences in body weights, the wet weights of the stomach, small intestine, cecum and large intestine were generally similar in AL and ER mice, suggesting that the gastrointestinal tract was spared during ER. In contrast, the wet weights of the lungs, kidneys, spleen, heart, pancreas and liver each differed by 40-120% between ER and AL mice. Intestinal transport adaptations develop gradually during ER, and the main mechanism underlying these adaptations is a dramatic increase in transport activity per milligram tissue.