CONTEXT: Entero-pancreatic hormone secretion has been reported during the pre-absorptive cephalic and gastric meal phases, but never with a blood sampling frequency providing a temporal resolution that allows close scrutiny and correlations with gastric emptying and glucose-absorption.

OBJECTIVE: We hypothesized that entero-pancreatic hormone secretion after nutrient ingestion would be rapid and correlate with gastric emptying and glucose absorption.

DESIGN AND SETTING: Two visits in a clinical research facility.

PARTICIPANTS: Ten healthy young men.

INTERVENTIONS: A 75g glucose drink (OG) and a liquid mixed meal (LMM) were ingested (t 0-2 min) on separate days. Acetaminophen and 3-O-methyl-D-glucopyranose (3-OMG) were added to the drinks to evaluate gastric emptying and glucose absorption, respectively. Arterialized venous blood was sampled (t -30,-20,-18,-16,-14,-12,-10,-8,-6,-4,-2, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 30 min).

MAIN OUTCOME MEASURES: Plasma glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), gastrin, cholecystokinin (CCK), glucagon, pancreatic polypeptide (PP), 3-OMG and glucose. Serum insulin, C-peptide and acetaminophen.

RESULTS: Acetaminophen increased 8min after OG(p<0.001) and LMM(p<0.05). 3-OMG; 8min after LMM(p<0.0001), 10min after OG(p=0.04). PP; 4min after LMM(p<0.03). Gastrin; 6min after LMM(p<0.003) and OG(p<0.003). CCK; 6min after LMM(p=0.0001). GIP; 8min after OG(p<0.05) and LMM(p<0.03). Glucose; 8min after OG(p<0.001), 12min after LMM(p<0.02). GLP-1; 12min after OG(p<0.01), 10min after LMM (p<0.01).. Insulin; 12min after LMM(p=0.02) and OG(p=0.002). C-peptide; 12min after OG(p=0.002) and LMM(p=0.04).

CONCLUSIONS: Early postprandial hormone responses show characteristic differences with regards to timing and amplitude, but also great individual differences. This should be considered when interpreting mean responses and designing study protocols.

CLINICALTRIALS.GOV NUMBER: NCT03543423.