Jones C J, Fox H
Invest Cell Pathol. 1978 Jul-Sep;1(3):217-25.
The placental content of malate dehydrogenase and lactate dehydrogenase has been studied at the ultrastructural level. In the trophoblast both enzymes have a predominantly mitochondrial localization although occasional membrane-bound extra-mitochondrial activity is also seen. As compared with the first trimester placenta, there is a highly significant decrease in the activity of both enzymes within the trophoblast at term; this may represent an adaptative change to reduce placental oxygen consumption and increase the amount of oxygen available to the fetus. In prolonged pregnancies, there is a continued decline in trophoblastic malate dehydrogenase activity but the lactate dehydrogenase activity tends to increase, these changes suggesting that there is a switch from oxidative pohosphorylation to anaerobic glycolysis. It is not clear whether this change to a less efficient mode of energy generation is due to an intrinsic ageing change within the trophoblast or is secondary to placental ischaemia.
已在超微结构水平上研究了苹果酸脱氢酶和乳酸脱氢酶在胎盘中的含量。在滋养层细胞中，这两种酶主要定位于线粒体，不过偶尔也可见到膜结合的线粒体外活性。与孕早期胎盘相比，足月时滋养层细胞内这两种酶的活性均显著降低；这可能代表一种适应性变化，以减少胎盘的氧消耗并增加可供胎儿利用的氧量。在过期妊娠中，滋养层苹果酸脱氢酶活性持续下降，但乳酸脱氢酶活性趋于增加，这些变化表明存在从氧化磷酸化向无氧糖酵解的转变。尚不清楚这种向效率较低的能量产生模式的转变是由于滋养层细胞内在的老化变化，还是继发于胎盘缺血。
