Elevated basal and post-feed glucagon-like peptide 1 (GLP-1) concentrations in the neonatal period

Abstract

Background: Glucagon-like peptide 1 (GLP-1) is an incretin hormone that stimulates glucose-induced insulin secretion, increases b-cell proliferation, neogenesis and b-cell mass. In adults, plasma concentrations of amidated GLP-1 are typically within the 5-10 pmol/l range in the fasting state and increases to w50 pmol/l after ingestion of a mixed meal. Research design and methods: We measured plasma glucose, insulin and amidated forms of GLP-1 prefeed and then at 20 and 60 min post-feed following ingestion of a 60-70 ml of standard milk feed in preterm (nZ10, 34-37 weeks) and term newborn infants (nZ12, 37-42 weeks). Reverse-phase fast protein liquid chromatography was used to characterise the molecular nature of the circulating GLP-1. Results: Mean birth weight was 3.18 kg and mean age at sampling for GLP-1 was 7.7 days. The mean basal GLP-1 concentration was 79.1 pmol/l, which increased to 156.6 pmol/l (G70.9, P!0.001) and 121.5 pmol/l (G59.2) at 20 and 60 min respectively. Reverse-phase chromatography analysis suggested that the majority of GLP-1 immunoreactivity (O75%) represented GLP-1 (7-36) amide and (9-36) amide. Conclusions: Basal and post-feed amidated GLP-1 concentrations in neonates are grossly raised with the major fractions of circulating GLP-1 being (7-36) amide and (9-36) amide. Elevated GLP-1 concentrations in the newborn period may have a role in regulating maturation of enteroendocrine system and also of increasing pancreatic b-cell mass and regeneration. The high levels of GLP-1 may be due to immaturity of the dipeptidyl peptidase IV and or lower glomerular filtration rate in the neonatal period. Further studies are required to understand the role of GLP-1 in the neonatal period.

Enteroinsular axis response to carbohydrates and fasting in healthy newborn foals

“…This finding indicates that the EIA in newborn foals is functional and highly responsive to nutrients contained in mare's milk, other than those administered in our study. Human newborn infants showed a similar GLP‐1 response after feeding milk . Mare's milk 1‐4 weeks postpartum is composed of approximately 2% fat, 3% protein, and 6% lactose .…”

“…It could also be that newborn foals have decreased DPP‐4 activity compared to horses. Similar to foals and horses, it has been shown that human infants have higher resting GLP‐1 concentrations than adults . The dynamics of incretin secretion over time in healthy foals remain to be investigated but preliminary work from our laboratory indicates that 3‐day‐old foals have lower GLP‐1 concentrations than at birth (L.M.R./R.E.T., personal communication).…”

Circulating GLP-1 in infants born small-for-gestational-age: breast-feeding versus formula-feeding

“…Our study design does not allow to infer when exactly those GLP-1 levels surge, but cross-sectional evidence from newborns aged 4-10 days suggests that this surge (to supra-adult concentrations) occurs within the first few days after birth. 11 The observation that pre-feeding GLP-1 levels are higher in SGA infants receiving FOF than in those receiving BRF during early infancy suggests that neonatal nutrition is a modulator of circulating GLP-1 in SGA infants and is thus a potential modulator of hypothalamic setpoints that relate to appetite and energy expenditure in subsequent life. [6][7][8][9] For example, higher concentrations of circulating GLP-1 during early infancy may be accompanied by lower hypothalamic sensitivity to GLP-1 in later life.…”

Influence of gestational age on serum incretin levels in preterm infants

“…Other studies also reported similar findings. 10,11 Kawamata et al 8 speculated that these differences between infants and adults in GIP or GLP-1 levels result from a difference in the amount of enteral feeding. In preterm infants, enteral feeding is usually every 3 h, which may stimulate GIP and GLP-1 secretion to a greater level in neonates than in older children and adults.…”