Factors affecting gluconeogenesis in the neonatal subhuman primate (Macaca mulatta)

Area of Science:

• Biochemistry
• Neonatal Physiology
• Primate Metabolism

Background:

• Gluconeogenesis is vital for maintaining blood glucose homeostasis, especially in neonates.
• Subhuman primates (Macaca mulatta) serve as a valuable model for studying human neonatal metabolism.
• Understanding neonatal gluconeogenic capacity is crucial for identifying metabolic vulnerabilities.

Purpose of the Study:

• To investigate the capacity for gluconeogenesis in newborn Macaca mulatta.
• To correlate blood glucose levels with gluconeogenic substrate availability and enzyme activity.
• To examine the relationship between serum-free fatty acids and glucose metabolism in neonates.

Main Methods:

• Studied 33 newborn Macaca mulatta in a basal steady state.
• Measured basal blood glucose, alanine, lactate, and serum-free fatty acid levels.
• Assessed hepatic and renal cortical content of key gluconeogenic enzymes.

Main Results:

• Basal blood glucose levels increased with postnatal age.
• Adequate gluconeogenic substrates (alanine, lactate) were present even when glucose and gluconeogenesis rates were low.
• Key gluconeogenic enzyme levels were low in the first week compared to adults.
• Low enzyme induction did not fully explain low blood glucose; serum-free fatty acids correlated with glucose and gluconeogenesis.

Conclusions:

• Neonatal primate gluconeogenesis is limited by low key enzyme levels, not substrate availability.
• Serum-free fatty acids play a significant role in regulating neonatal glucose levels and gluconeogenesis.
• These findings highlight potential metabolic challenges in primate neonates requiring further investigation.