Weijs P J, Schreurs V V, Grooten H N
Department of Human and Animal Physiology, Wageningen Agricultural University, The Netherlands.
Br J Nutr. 1995 Feb;73(2):253-8. doi: 10.1079/bjn19950027.
During pregnancy a higher amino acid requirement may be expected, but the increase in food intake does not match the increased growth rate during pregnancy. It is hypothesized that amino acid utilization can be increased during both fasting and feeding in order to account for the increased requirement. Therefore mature female rats (20 weeks old) were investigated before and at day 18 of pregnancy. Rats were fed on a high-protein (HP) diet (210 g casein/kg diet) for 3 weeks and fasted overnight. Rats were then subjected to an 8 h constant infusion of L-[1-14C]leucine with continuous measurement of expired 14CO2 (as a percentage of the infused dose). After 3 h infusion a 5 g HP or low-protein (LP; 75 g casein/kg diet) meal was offered for 30 min. Pregnant rats had a significantly lower percentage leucine oxidation in the fasted state (12.5 (SE 0.7) v. 15.9 (SE 1.1)%; P < 0.05), which suggests improved reutilization of leucine. Meal ingestion resulted in a fast increase in 14CO2 expiration. After the LP meal the level of 14CO2 expiration decreased again after the acute response (0-1.5 h), but this was not the case after the HP meal. After the HP meal (average 1.5-5 h), no difference was observed between pregnant and non-pregnant status (36.8 (SE 1.6) v. 35.0 (SE 2.5)%). After the LP meal (average 1.5-5 h), however, the percentage leucine oxidation tended to be lower in pregnant rats but this difference did not reach statistical significance (19.7 (SE 1.1) v. 25.8 (SE 2.8)%).(ABSTRACT TRUNCATED AT 250 WORDS)
在怀孕期间，可能预期对氨基酸的需求量会更高，但食物摄入量的增加并不与孕期增加的生长速率相匹配。据推测，为了满足增加的需求，在禁食和进食期间氨基酸的利用率都可以提高。因此，对成年雌性大鼠（20周龄）在怀孕前和怀孕第18天进行了研究。大鼠被喂食高蛋白（HP）饮食（210克酪蛋白/千克饮食）3周，然后禁食过夜。接着给大鼠持续8小时输注L-[1-¹⁴C]亮氨酸，并连续测量呼出的¹⁴CO₂（占输注剂量的百分比）。输注3小时后，提供5克HP或低蛋白（LP；75克酪蛋白/千克饮食）餐食，持续30分钟。怀孕大鼠在禁食状态下亮氨酸氧化的百分比显著更低（12.5（标准误0.7）对15.9（标准误1.1）%；P<0.05），这表明亮氨酸的再利用得到改善。进食餐食导致¹⁴CO₂呼出迅速增加。LP餐食后，¹⁴CO₂呼出水平在急性反应后（0 - 1.5小时）再次下降，但HP餐食后并非如此。HP餐食后（平均1.5 - 5小时），怀孕和未怀孕状态之间未观察到差异（36.8（标准误1.6）对35.0（标准误2.5）%）。然而，LP餐食后（平均1.5 - 5小时），怀孕大鼠亮氨酸氧化的百分比趋于更低，但这种差异未达到统计学显著性（19.7（标准误1.1）对25.8（标准误2.8）%）。（摘要截选至250字）
