Renal responses to amino acids in the sheep fetus.
Renal responses to amino acids in the sheep fetus.
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绵羊胎儿的肾脏对氨基酸的反应。
DOI：
10.1152/ajpregu.1996.270.6.r1226
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Davis,LE
中科院分区：
文献类型：
--
作者：
Woods,LL;Hohimer,AR;Davis,LE
已知成年动物和人类在急性蛋白质负荷或氨基酸输注时增加肾血流量和肾小球滤过率（GFR）；然而，这种现象的成因尚不清楚。本研究旨在验证一种假设，即尽管胎儿的氨基酸基线水平通常较高，但血浆氨基酸的增加会刺激出生前GFR的增加。8只慢性仪器化胎羊（妊娠126 +/- 1天）输注氨基酸混合物（0.15和0.30 mmol）。公斤。最低为1注射)。血浆α -氨基氮水平分别从7.1 +/- 0.3、13.0 +/- 0.9和25.5 +/- 2.1 mg/dl显著升高，GFR分别从3.2 +/- 0.4、4.0 +/- 0.5和4.6 +/- 0.5 ml/min显著升高。动脉压没有变化。在氨基酸输注过程中，肾脏氨基酸重吸收在各时间点均显著增加，在最后一个清除率时达到对照组的近5倍。在整个输注过程中，Na+的再吸收也增加。Na+， K+和Cl-排泄仅在最后一个时间点显著增加。这些数据表明，氨基酸诱导的超滤机制甚至在绵羊出生前就存在并发挥作用。由于已知母体的饮食模式和蛋白质摄入会改变母体血浆氨基酸水平，并且氨基酸会主动通过胎盘运输，因此我们的研究结果表明，母体蛋白质摄入的急性和慢性变化都可能改变胎儿的肾功能。
Adult animals and humans are known to increase renal blood flow and glomerular filtration rate (GFR) in response to an acute protein load or amino acid infusion; however, the ontogeny of this phenomenon is not known. This study was designed to test the hypothesis that, despite normally high baseline amino acid levels in the fetus, increases in plasma amino acids stimulate increases in GFR before birth. Eight chronically instrumented fetal sheep (126 +/- 1 days gestation) were infused with a mixture of amino acids (0.15 and 0.30 mmol . kg-1 . min-1 i.v.). Plasma alpha-amino nitrogen levels increased significantly from 7.1 +/- 0.3 to 13.0 +/- 0.9 and 25.5 +/- 2.1 mg/dl, respectively, in response to the two doses, and GFR increased significantly from 3.2 +/- 0.4 to 4.0 +/- 0.5 and 4.6 +/- 0.5 ml/min, respectively. Arterial pressure did not change. Renal amino acid reabsorption was significantly increased at all time points during the amino acid infusion, reaching a value nearly five times that of control by the last clearance period. Na+ reabsorption was also increased throughout the infusion. Na+, K+, and Cl- excretions increased significantly only at the very last time point. These data indicate that the mechanism or mechanisms responsible for amino acid-induced hyperfiltration are present and functional even before birth in the sheep. Because maternal eating patterns and protein intake are known to change maternal plasma amino acid levels and amino acids are actively transported across the placenta, our findings suggest that both acute and chronic changes in maternal protein intake may alter fetal renal function.