The Effect of Premature Delivery on the Development of Gluconeogenic Enzymes in the Guinea Pig

Abstract

Extract: The activities of key gluconeogenic enzymes in the livers of newborn guinea pigs were monitored as a function of time following birth either vaginally at term or prematurely by cesarian section at 62 days of gestation. The activity of hepatic glucose-6-phosphatase rose dramatically from 1.40 ± 0.26 μmol/min/g at birth to a maximum of 6.8 ± .0.9 μmol/min/g at 24 hr in prematurely delivered animals although there was little significant change in activity in full term animals. The activity of hepatic fructose-1,6− diphosphatase and mitochondrial phosphoenolpyruvate carboxykinase changed little over the first 3 days of life in either full term or premature animals. Cytosolic phosphoenolpyruvate carboxykinase, on the other hand, had low activity at birth being 0.11 ± 0.03 μmol/min/g in full term and 0.06 ± 0.04 μmol in premature animals rising to values of 0.71 ± 0.06 and 1.12 ± 0.12 μmol/min/g, respectively, at 24 hr of life. Pyruvate carboxylase activities in the premature animals remained significantly lower than those in full term animals in the first 72 hr of life. Transient hypoglycemia was evident in the prematurely delivered animals, but not in the full term animals, the blood glucose values being 82 ± 7 mg/100 ml for the full term animals and 20 ± 8 mg/100 ml for the premature infants at 2 hr of life. Speculation: Premature delivery of the newborn guinea pig leads to neonatal hypoglycemia which is due to a combination of deficient hepatic glycogen and compromised gluconeogenic enzyme activity.