LEUCINE METABOLISM IN HUMAN NEWBORNS
LEUCINE METABOLISM IN HUMAN NEWBORNS
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DOI：
10.1152/ajpendo.1987.253.6.e608
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发表时间：
1987-12-01
影响因子：
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通讯作者：
KALHAN, SC
中科院分区：
文献类型：
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作者：
DENNE, SC;KALHAN, SC
本研究旨在 1) 确定新生儿出生体重和亮氨酸代谢之间是否存在关系，2) 比较快速生长和发育时期（即新生儿）与恒定非生长时期（即成人）的亮氨酸和能量代谢。使用引发的恒定L-[1-13C]亮氨酸输注结合呼吸量热法，测量了 12 名正常足月新生儿和 11 名正常成人的吸收后状态下的亮氨酸动力学和能量消耗。观察到新生儿出生体重与亮氨酸通量之间存在显着正相关。与成人相比，新生儿每公斤体重的亮氨酸通量明显更高，亮氨酸氧化和能量消耗也是如此。当标准化为代谢体重（W0.75）时，新生儿和成人的能量消耗、亮氨酸通量和氧化率相似。亮氨酸通量与体重关系的异速生长指数 (0.80) 几乎等于描述能量消耗与体重关系的异速指数 (0.79)，并且两者都与代谢体重指数 0.75 相似。这些数据表明以下内容。 1) 新生儿出生体重和蛋白质代谢之间存在关系，这可以通过以微摩尔每千克每小时表示的亮氨酸通量与出生体重之间的相关性来反映。据推测，这种关系可能是之前蛋白质和能量供应差异的结果。 2) 新生儿测量到的高亮氨酸通量可能反映了这一发育时期甚至禁食期间发生的蛋白质快速重塑。 3）当标准化为代谢体重时，新生儿和成人的亮氨酸动力学和能量消耗的相似值以及将体重与亮氨酸通量和能量消耗相关的几乎相等的异速生长指数支持亮氨酸（可能还有蛋白质）和能量代谢之间的密切关系，至少在人类生长的极端情况下。
The present study was designed to 1) determine whether a relationship exists between newborn birth weight and leucine metabolism and 2) compare leucine and energy metabolism in a period of rapid growth and development (i.e., newborn) with a constant nongrowth period (i.e., adult). Leucine kinetics and energy expenditure were measured in the postabsorptive state in 12 normal full-term newborns in early neonatal life and in 11 normal adults using a primed constant L-[1-13C]leucine infusion combined with respiratory calorimetry. A significant positive correlation between newborn birth weight and leucine flux was observed. Leucine flux per kilogram body weight was significantly greater in newborns compared with adults, as was leucine oxidation and energy expenditure. When normalized to metabolic body weight (W0.75), newborns and adults had similar rates of energy expenditure, leucine flux, and oxidation. The allometric exponent relating leucine flux to body weight (0.80) was nearly equivalent to that describing the energy expenditure-to-body weight relationship (0.79) and both were similar to the 0.75 metabolic weight exponent. These data suggest the following. 1) A relationship exists between newborn birth weight and protein metabolism, as reflected by the correlation between leucine flux when expressed as micromoles per kilogram per hour and birth weight. It is speculated that this relationship may be the result of differences in previous protein and energy supplies. 2) The high rate of leucine flux measured in newborns probably reflects the rapid remodeling of protein that occurs in this period of development, even during fasting. 3) The similar values in newborns and adults of leucine kinetics and energy expenditure when normalized to metabolic body weight and the nearly equivalent allometric exponents relating body weight to leucine flux and energy expenditure support a close relationship between leucine (and possibly protein) and energy metabolism, at least at the extremes of human growth.