Rosso P
Fed Proc. 1980 Feb;39(2):250-4.
Maternal malnutrition in humans and also in the rat interferes with normal placental growth as reflected by a lower weight, smaller placental size, and reduced DNA content. The affected placentas also have a reduced peripheral villous mass and villous surface. Biochemical studies have revealed a reduced polysome/monosome ratio and higher levels of alkaline ribonuclease activity. However, the rate of protein synthesis in a cell free system, expressed per milligram of rRNA, is not impaired. The composition of the placenta is also altered by malnutrition. Reduced concentrations of ash, hydroxyproline, and fat have been described in human placentas and reduced glycogen and putrescine concentrations have been described in the rat placenta. The functional implications of some of these changes are still unclear. In malnourished women a reduced estriol and pregnanediol excretion have been reported. Malnourished rats near term have a reduced maternal-fetal transfer of alpha-aminoisobutyric acid and glucose, but is is still unclear to what extent the reduced transfer is due to placental factors or preplacental factors such as reduced placental blood flow, also present in malnourished animals.
人类以及大鼠的母体营养不良会干扰胎盘的正常生长，这表现为体重降低、胎盘尺寸变小以及DNA含量减少。受影响的胎盘外周绒毛团和绒毛表面积也会减小。生化研究显示多核糖体/单核糖体比率降低，碱性核糖核酸酶活性水平升高。然而，以每毫克rRNA表示的无细胞系统中的蛋白质合成速率并未受损。营养不良还会改变胎盘的组成。据报道，人类胎盘的灰分、羟脯氨酸和脂肪浓度降低，大鼠胎盘的糖原和腐胺浓度降低。其中一些变化的功能影响仍不清楚。据报道，营养不良的女性雌三醇和孕二醇排泄减少。接近足月的营养不良大鼠，其母体向胎儿的α-氨基异丁酸和葡萄糖转运减少，但这种转运减少在多大程度上是由于胎盘因素，还是由于胎盘前因素，如营养不良动物中也存在的胎盘血流量减少所致尚不清楚。
