ExtractFetal liver obtained from legal abortions was cultured in vitro. The activities of pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (GPD), phosphoenolpyruvate carboxykinase (PEPK), and tyrosine transaminase (TTA) were determined immediately after abortion and after culturing for 24 hr. Changes due to culturing were the following: a loss in protein content (-45%), a decrease in PK ( -16%) and GDP (-40%) activities, a rise in PEPK activity ( + 180%) and, a fall in TTA activity (-10%) in fetuses younger than 16 weeks and a rise in older fetuses (+60%).Dibutyryl cyclic AMP (DcAMP) added to the cultures for the last 5 hr of incubation raised the activities of PEPK and TTA by 35% and 50%, respectively. Addition of oleic acid together with DL-carnitine had the same effect on PEPK only (+35%). PEPK activity was found to be increased 10-fold in a 12.5-week-old fetus, the mother of whom had been receiving prednisolone.It was also found that TTA and cytoplasmic PEPK activities decrease with increasing fetal age.
SpeculationOur data indicate that it is possible to induce TTA and PEPK very early in fetal life. It is hence possible that certain drugs and hormones applied to the mother have an effect on liver enzyme systems in the young fetus. It seems important to establish whether such induced changes have a deleterious effect on further fetal development.