Ahokas R A, Lahaye E B, Anderson G D, Lipshitz J
J Nutr. 1981 Dec;111(12):2052-8. doi: 10.1093/jn/111.12.2052.
Maternal net weight gain, plasma clearance, and placental and fetal accumulation of I.V. administered 14C-alpha amino isobutyric acid (AIB) on day 20 of gestation were measured in pregnant rats: 1) fed ad libitum throughout gestation (Control), 2) fed 50% of the normal daily food intake during the last week of gestation (catabolic phase), and 3) fed 50% of the normal daily food intake throughout gestation. Dietary restriction during the catabolic phase only resulted in a loss of 54% of the net maternal weight gained during the first two weeks of gestation, while dietary restriction throughout gestation resulted in a net loss of 5.4% of the dams prepregnant weight. Both dietary regimens caused significant growth retardation of the fetus. Maternal plasma clearance of AIB was rapid and occurred at the same rate in all three groups. Placental accumulation and transfer of AIB to the fetus was reduced relative to the controls only in dams fed the restricted diet throughout gestation. Fetal to placental AIB concentration ratios were similar for each group indicting no difference in ability of placentas to release amino acid into the fetal circulation. The results indicate that mechanisms other than reduced nutrient transfer may be responsible for fetal growth retardation induced by maternal malnutrition during the catabolic phase of pregnancy only.
在妊娠第20天，对妊娠大鼠静脉注射14C-α-氨基异丁酸（AIB）后的母体净体重增加、血浆清除率以及胎盘和胎儿的蓄积情况进行了测量：1）整个妊娠期自由采食（对照组）；2）在妊娠最后一周采食正常每日食物摄入量的50%（分解代谢期）；3）整个妊娠期采食正常每日食物摄入量的50%。仅在分解代谢期进行饮食限制导致妊娠前两周母体净体重增加量减少了54%，而整个妊娠期进行饮食限制导致母鼠孕前体重净减少5.4%。两种饮食方案均导致胎儿显著生长迟缓。AIB的母体血浆清除迅速，且三组清除速率相同。仅在整个妊娠期采食受限饮食的母鼠中，AIB的胎盘蓄积及向胎儿的转运相对于对照组有所减少。每组胎儿与胎盘的AIB浓度比相似，表明胎盘向胎儿循环释放氨基酸的能力无差异。结果表明，在妊娠分解代谢期，除营养物质转运减少外，其他机制可能是母体营养不良所致胎儿生长迟缓的原因。
