Glucose and lactate kinetics in the neonate

Area of Science:

• Metabolic Physiology
• Neonatal Medicine
• Endocrinology

Background:

• Neonatal glucose homeostasis is critical for survival and development.
• Understanding ontogeny of glucose metabolism in neonates is essential.
• Premature infants present unique metabolic challenges.

Purpose of the Study:

• To evaluate the ontogeny of neonatal glucose homeostasis.
• To compare glucose and lactate production rates in preterm, full-term neonates, and adults.
• To assess the potential for gluconeogenesis from lactate in neonates.

Main Methods:

• Measured glucose production rate (Ra glucose) and lactate production rate (Ra lactate) using isotope dilution.
• Studied nine preterm neonates, five full-term neonates, and six non-pregnant, non-diabetic adults.
• Calculated the ratio of Ra lactate to Ra glucose to estimate gluconeogenesis potential.

Main Results:

• Both preterm and full-term neonates exhibited significantly higher Ra glucose and Ra lactate compared to adults.
• Ra glucose (preterm): 27.7 +/- 2.8 mumol.kg-1 min-1; Ra glucose (term): 28.9 +/- 3.9 mumol.kg-1 min-1.
• Ra lactate (preterm): 100 +/- 11.9 mumol.kg-1 min-1; Ra lactate (term): 77.2 +/- 13.0 mumol.kg-1 min-1.
• The ratio of Ra lactate/Ra glucose, indicating gluconeogenesis potential, was similar between preterm and term neonates.

Conclusions:

• Neonates, both preterm and full-term, demonstrate elevated glucose and lactate production rates compared to adults.
• The gluconeogenic capacity from lactate appears comparable between preterm and term infants.
• These findings highlight distinct metabolic adaptations in neonatal glucose homeostasis.