Alanine and lactate as gluconeogenic substrates during late gestation

Rates of alanine incorporation into glucose by isolated liver cells of fed rats are 5-fold higher than those observed when lactate was used as substrate. The rates of gluconeogenesis from alanine and lactate in isolated liver cells of fed pregnant rats increase 50 and 200-400%, respectively, over virgins during the last 3 days of gestation. The results support the existence of an increase in the alanine-glucose cycle in the late pregnancy as an important homeostatic pathway in the supply of glucose to the growing fetus.