Glucose production in response to glucagon is comparable in preterm AGA and SGA infants

Area of Science:

• Neonatal physiology
• Endocrinology
• Metabolic research

Background:

• Small-for-gestational-age (SGA) infants often exhibit lower plasma glucose concentrations compared to appropriate-for-gestational-age (AGA) infants.
• This hypoglycemia is attributed to impaired glucose production, presumed to stem from reduced liver glycogen stores in SGA neonates.
• Glucagon's effect on glucose production serves as a proxy for assessing liver glycogen content.

Purpose of the Study:

• To investigate and compare the impact of glucagon on glucose kinetics in preterm AGA and SGA infants.
• To evaluate the hypothesis of diminished liver glycogen stores in preterm SGA infants.

Main Methods:

• Stable isotope tracers were employed to measure glucose production and gluconeogenesis.
• Measurements were conducted in 5 preterm AGA and 5 preterm SGA infants (3-6 days postnatal age).
• Infants received a glucagon bolus, with glucose kinetics assessed immediately before and for 1 hour post-administration.

Main Results:

• Plasma glucose concentration and glucose production significantly increased post-glucagon administration in both groups (P<0.05 and P<0.0001, respectively).
• The observed increases in glucose production and concentration were comparable between preterm AGA and SGA infants.
• Glycogenolysis accounted for 75-80% of the augmented glucose production following glucagon stimulation.

Conclusions:

• The response to glucagon, indicated by increased glucose production, was similar in preterm AGA and SGA infants.
• This response was primarily driven by enhanced glycogenolysis, suggesting adequate liver glycogen stores.
• The findings do not support the hypothesis that preterm SGA infants have lower liver glycogen content than preterm AGA infants after the first postnatal day.