ENERGY-METABOLISM AND GLYCOLYSIS IN HUMAN PLACENTAL TROPHOBLAST CELLSDURING DIFFERENTIATION

Energy metabolism and glycolysis of normal human term placental tropho blast in two-sided culture was investigated during differentiation fro m cytotrophoblast to syncytiotrophoblast, because glycogen metabolism is abnormal in several trophoblast related pregnancy diseases, includi ng pre-eclampsia. After initial recovery of energy and cytoplasmic NAD H/NAD(+) redox by 24 h of culture, measures of cellular energy state, [ATP], [ADP], [ATP]/[ADP] ratio, ([ATP] + [ADP] + [AMP]), [ATP]/([ATP] + [ADP] + [AMP]) and energy charge remained essentially constant unti l 72 h, despite periods of increased energy turnover. At 24 h there wa s a burst of glycogenolysis, and glycolysis indicated by increased lac tate production, which coincided with formation of syncytium. Subseque ntly, there was no resynthesis nor further breakdown of glycogen. At 4 8 h, oxygen consumption temporarily increased substantially, without i ncreased glycolysis, during functional differentiation of the syncytio trophoblast. Glucose uptake was constant and largely from the basal (i n vivo fetal racing) side. Lactate output into the basal fetal medium was twice as fast as that into the microvillous substantial relatively constant aerobic glycolysis occurs, but that during increased energy demand cytotrophoblast depends on both glycolytic and aerobic energy p roduction whereas syncytiotrophoblast relies on aerobic metabolism. (C ) 1997 Elsevier Science B.V.