Fetal and neonatal metabolism in the pup of a canine diabetic mother. Fasting circulating fuels and neonatal glucose turnover.

The metabolic effects of previously induced alloxan diabetes were investigated among fasted newborn dogs during the first day of life. Maternal insulin-dependent diabetes resulted in enhanced maternal and fetal blood glucose and ketone bodies, while postnatal levels of these substrates were not altered. Plasma insulin levels were augmented in the fetus and neonate (3 and 6 h of age) of the diabetic mother, while pancreatic insulin content was also enhanced at fetal and 3 h of age. Circulating free fatty acid levels were diminished among pups born to diabetic mothers (IDM pups) at 3 and 6 h of age, while glycerol levels were unaffected. Nevertheless, plasma triglyceride concentrations were elevated in pups of diabetic mothers during fetal and at 3 and 6 h of newborn fasting. Systemic glucose turnover was not altered in pups of diabetic mothers at 3, 9, or 24 h, while at 6 h, glucose turnover appeared enhanced in IDM pups, which was due in part to a decline of glucose production between 3 and 6 h among controls. Gluconeogenesis was attenuated at 9 h of age among IDM pups, but increased by 24 h of age. Hyperinsulinism in the presence of unaltered glucose turnover with attenuated free fatty acid levels suggest that neonatal canine glucose production from hepatic glycogen is less sensitive to insulin's effect than is the lipolysis-lipid reesterification cycle. Gluconeogenesis from lactate may be unnecessary if glycogenolysis is able to support systemic and hepatic substrate requirements, while insulin mediated lipid synthesis may augment tissue triglyceride deposits.