Increased sympathetic nervous system activity in rats fed a low-protein diet.
Increased sympathetic nervous system activity in rats fed a low-protein diet.
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喂食低蛋白饮食的大鼠交感神经系统活动增加。
DOI：
10.1152/ajpregu.1985.248.5.r627
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Landsberg,L
中科院分区：
文献类型：
--
作者：
Young,JB;Kaufman,LN;Saville,ME;Landsberg,L
为了检查饲喂限制蛋白质饮食的动物的交感神经系统（SNS）功能状态，测定了饲喂含22%蛋白质（以酪蛋白计）或7%蛋白质（差异由蔗糖弥补）的等热量密度合成饮食的大鼠心脏和肩胛间棕色脂肪组织（IBAT）中的[3 H]去甲肾上腺素（[3 H]-NE）周转率。由于酪氨酸的饮食可用性是SNS对蛋白质摄入的反应的潜在介体，因此还测试了第三种饮食（7%蛋白质补充酪氨酸）。12天后，7%蛋白质喂养使心脏[~ 3 H]-NE周转率增加35-70%，IBAT增加93-103%。当较小的动物喂食合成饲料4-5周时，给予蛋白质限制配方的动物中的交感神经刺激也很明显，尽管由于正常组和蛋白质限制组之间的体型显著差异而导致的比较问题使这种反应的证明变得复杂。添加酪氨酸（足以使血浆和脑酪氨酸水平正常化）对蛋白质缺乏饮食诱导的NE周转的刺激没有影响。同样，在食用7%蛋白质饮食的动物中观察到的尿NE排泄增加不受补充酪氨酸的影响。然而，尿多巴胺排泄，是独特的和惊人的升高与恢复饮食酪氨酸喂养的低蛋白饮食的动物。因此，在饮食中用蔗糖等热量取代酪蛋白激活了心脏和IBAT中的SNS，这是一种与饮食酪氨酸限制无关的反应。
To examine the state of sympathetic nervous system (SNS) function in animals fed a protein-restricted diet, [3H] norepinephrine ([3H]-NE) turnover was measured in heart and interscapular brown adipose tissue (IBAT) of rats fed synthetic diets of equal caloric density containing 22% protein (as casein) or 7% protein (the difference being made up by sucrose). Because dietary availability of tyrosine is a potential mediator of SNS responses to protein ingestion, a third diet (7% protein supplemented with tyrosine) was also tested. After 12 days dietary preparation [3H]-NE turnover was increased 35-70% in heart by 7% protein feeding and 93-103% in IBAT. When smaller animals were fed the synthetic diets for 4-5 wk, sympathetic stimulation in those given the protein-restricted formula was also apparent, although demonstration of this response was complicated by comparative problems due to the marked differences in body size between normal and protein-restricted groups. Addition of tyrosine (sufficient to normalize plasma and brain tyrosine levels) was without effect on the stimulation of NE turnover induced by the protein-deficient diet. Similarly, augmented urinary NE excretion observed in animals consuming the 7% protein diet was unaffected by supplemental tyrosine. Urinary dopamine excretion, however, was uniquely and strikingly elevated with restoration of dietary tyrosine to animals fed the low-protein diet. Thus isocaloric substitution of sucrose for casein in the diet activates the SNS in heart and IBAT, a response unrelated to limitation of dietary tyrosine.