Thureen Patti J, Baron Karen A, Fennessey Paul V, Hay Willaim W
Perinatal Research Center, Department of Pediatrics, University of Colorado Health Sciences Center, Denver, Colorado, 80262, USA.
Pediatr Res. 2002 Apr;51(4):464-71. doi: 10.1203/00006450-200204000-00011.
Arginine (A) may play a significant role in fetal growth, by stimulating insulin secretion and as a precursor for both polyamine synthesis and nitric oxide production. To determine whether increased maternal plasma A concentrations can enhance delivery of A to the fetus, uterine, umbilical, and net uteroplacental (UP) A uptake rates were measured in 12 pregnant ewes at 129.6 +/- 0.4 d gestation (mean +/- SEM) during normal and after 3 h of increased maternal plasma A concentrations. With a 2.7-fold increase in maternal plasma A concentrations (p < 0.001), there were significant increases in uterine A uptake (13.8 +/- 1.0 to 41.3 +/- 7.7 micromol/min, p < 0.005), umbilical A uptake (3.3 +/- 0.5 to 5.2 +/- 0.8 micromol.min(-1).kg(-1) fetus, p < 0.005), UP A uptake (17.8 +/- 6.2 to 89.2 +/- 20.3 micromol.min(-1).kg(-1) placenta, p < 0.01), fetal arterial A concentration (98.7 +/- 6.3 to 137.1 +/- 9.9 microM, p < 0.001), maternal A disposal rate (143.7 +/- 9.4 to 217.0 +/- 6.7 micromol/min, p < 0.001), fetal A disposal rate (7.9 +/- 0.8 to 9.9 +/- 1.1 micromol.min(-1).kg(-1), p < 0.05), fetal A oxidation rate (1.31 +/- 0.24 to 1.84 +/- 0.36 micromol.min(-1).kg(-1), p < 0.05), and plasma insulin concentration in both fetus (16 +/- 2 to 20 +/- 2 microU/mL, p < 0.001) and mother (24 +/- 3 to 32 +/- 4 microU/mL, p < 0.001). Thus, increased maternal plasma A concentration increases maternal, UP, and fetal A net uptake, and increases insulin secretion in mother and fetus. The 4.2-fold larger increase in UP than net fetal A uptake could represent preferential UP A metabolism relative to fetal A metabolism, relatively limited placental-fetal A transport capacity compared with uterine A uptake capacity, or both; responsible mechanisms remain unknown.
精氨酸（A）可能在胎儿生长中发挥重要作用，它可刺激胰岛素分泌，同时作为多胺合成和一氧化氮生成的前体。为了确定母体血浆A浓度升高是否能增强A向胎儿的输送，对12只妊娠母羊在妊娠129.6±0.4天（平均值±标准误）时，分别在正常情况下以及母体血浆A浓度升高3小时后，测量子宫、脐部和子宫胎盘（UP）的A摄取率。母体血浆A浓度增加2.7倍（p<0.001）后，子宫A摄取量显著增加（从13.8±1.0微摩尔/分钟增至41.3±7.7微摩尔/分钟，p<0.005），脐部A摄取量（从3.3±0.5微摩尔·分钟⁻¹·千克⁻¹胎儿增至5.2±0.8微摩尔·分钟⁻¹·千克⁻¹胎儿，p<0.005），UP的A摄取量（从17.8±6.2微摩尔·分钟⁻¹·千克⁻¹胎盘增至89.2±20.3微摩尔·分钟⁻¹·千克⁻¹胎盘，p<0.01），胎儿动脉A浓度（从98.7±6.3微摩尔/升增至137.1±9.9微摩尔/升，p<0.001），母体A清除率（从143.7±9.4微摩尔/分钟增至217.0±6.7微摩尔/分钟，p<0.001），胎儿A清除率（从7.9±0.8微摩尔·分钟⁻¹·千克⁻¹增至9.9±1.1微摩尔·分钟⁻¹·千克⁻¹，p<0.05），胎儿A氧化率（从1.31±0.24微摩尔·分钟⁻¹·千克⁻¹增至1.84±0.36微摩尔·分钟⁻¹·千克⁻¹，p<0.05），以及胎儿（从16±2微单位/毫升增至20±2微单位/毫升，p<0.001）和母体（从24±3微单位/毫升增至32±4微单位/毫升，p<0.001）的血浆胰岛素浓度。因此，母体血浆A浓度升高会增加母体、UP和胎儿的A净摄取量，并增加母体和胎儿的胰岛素分泌。UP的A摄取量增加幅度比胎儿A净摄取量增加幅度大4.2倍，这可能代表相对于胎儿A代谢而言，UP对A的代谢具有优先性，或者与子宫A摄取能力相比，胎盘 - 胎儿A转运能力相对有限，或者两者皆有；具体机制尚不清楚。
