TY - JOUR
T1 - Renal responses to amino acids in the sheep fetus
AU - Woods, Lori L.
AU - Hohimer, A. Roger
AU - Davis, Lowell E.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1996/6
Y1 - 1996/6
N2 - 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 iv). Plasma α-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 C1 excretions increased significantly only st 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.
AB - 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 iv). Plasma α-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 C1 excretions increased significantly only st 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.
KW - dietary protein
KW - glomerular filtration rate
KW - kidney
KW - pregnancy
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U2 - 10.1152/ajpregu.1996.270.6.r1226
DO - 10.1152/ajpregu.1996.270.6.r1226
M3 - Article
C2 - 8764287
AN - SCOPUS:0029820705
SN - 0363-6119
VL - 270
SP - R1226-R1230
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 6 39-6
ER -