The role of hepatic control of glucose homeostasis in the etiology of neonatal hypo- and hyperglycemia.

Precise control of glucose homeostasis is well recognized in the adult. Going from a period of complete dependence on the maternal organism for delivery of substrate, the fetus is born not only with a need to furnish himself with glucose for energy and rapid growth but also with the need to maintain a balance between glucose deficiency and excess. This is especially difficult because of the intermittent nature of exogenous oral intake in the neonatal period. Development of glucose homeostasis requires a balance between substrate availability (both absolute and relative) and coordination of hormonal, neural and enzymatic systems. The large number of conditions producing or associated with both hypo- and hyperglycemia in the newborn, especially the low birth weight or sick neonate, emphasizes this vulnerability. Newer techniques including stable isotope methodology, now being employed with increasing frequency, will help define maturation of neonatal carbohydrate homeostasis and further clarify nutritional requirements in this transitional period.