Effects of passage through the digestive tract on incretin secretion: Before and after birth

AIMS/INTRODUCTION: It was reported that fetuses secrete endogenous incretin; however, the stimulants of fetal incretin secretion are not fully understood. To investigate the association between the passage of amniotic fluid through the intestinal tract and fetal secretion of incretin, we analyzed umbilical cord incretin levels of infants with duodenum atresia. MATERIALS AND METHODS: Infants born from July 2017 to July 2019 (infants with duodenum atresia and normal term or preterm infants) were enrolled. We measured and compared the concentrations of glucagon‐like peptide‐1 (GLP‐1) and gastric inhibitory peptide/glucose‐dependent insulinotropic polypeptide (GIP) in the umbilical vein and preprandial blood samples after birth. RESULTS: A total of 98 infants (47 term, 46 preterm and 5 with duodenum atresia) were included. In patients with duodenum atresia, umbilical vein GLP‐1 and GIP levels were the same as those in normal infants. In postnatal samples, there were positive correlations between the amount of enteral feeding and preprandial serum concentrations of GLP‐1 (r = 0.47) or GIP (r = 0.49). CONCLUSIONS: Our results show that enteral feeding is important for secretion of GLP‐1 and GIP in postnatal infants, whereas the passage of amniotic fluid is not important for fetal secretion of GLP‐1 and GIP. The effect of ingested material passing through the digestive tract on incretin secretion might change before and after birth. Other factors might stimulate secretion of GLP‐1 and GIP during the fetal period.