TY - JOUR

T1 - Incretin hormone and insulin responses to oral versus intravenous lipid administration in humans

AU - Lindgren, Ola

AU - Carr, Richard D

AU - Deacon, Carolyn F

AU - Holst, Jens Juul

AU - Pacini, Giovanni

AU - Mari, Andrea

AU - Ahrén, Bo

PY - 2011/8

Y1 - 2011/8

N2 - Context: The incretin effect is responsible for the higher insulin response to oral glucose than to iv glucose at matching glucose levels. It is notknownwhetherthis effect is restricted to glucose only. Objective: The aim of the study was to examine whether insulin and incretin hormone responses are higher after oral vs. iv challenge of a lipid emulsion with matching triglyceride levels in humans. Design, Settings, and Participants: A lipid emulsion (Intralipid) was administered orally (3 ml/kg) or iv (variable infusion rates to match triglyceride levels after oral ingestion) in healthy lean males (n 12) at a University Clinical Research Unit. Samples were collected during 300 min. Main Outcome Measures:Wemeasured the suprabasal area under the curve for insulin, glucagonlike peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and the insulin secretory rate based on C-peptide levels by deconvolution. Results: Triglyceride levels increased similarly after oral and iv lipid; also, glucose and free fatty acid levels were similar in the two tests. Oral lipid elicited a clear insulin and C-peptide response, whereas no insulin or C-peptide responses were observed during iv lipid. Total and intact GIP and GLP-1 levels both increased after oral lipid administration but were not significantly altered after iv lipid. Conclusions: At matching triglyceride levels and with no difference in glucose and free fatty acid levels, oral lipid ingestion but not iv lipid infusion elicits a clear insulin response in association with increased GIP and GLP-1 concentrations. This may suggest that the incretin hormones also contribute to the islet response to noncarbohydrate nutrients.

AB - Context: The incretin effect is responsible for the higher insulin response to oral glucose than to iv glucose at matching glucose levels. It is notknownwhetherthis effect is restricted to glucose only. Objective: The aim of the study was to examine whether insulin and incretin hormone responses are higher after oral vs. iv challenge of a lipid emulsion with matching triglyceride levels in humans. Design, Settings, and Participants: A lipid emulsion (Intralipid) was administered orally (3 ml/kg) or iv (variable infusion rates to match triglyceride levels after oral ingestion) in healthy lean males (n 12) at a University Clinical Research Unit. Samples were collected during 300 min. Main Outcome Measures:Wemeasured the suprabasal area under the curve for insulin, glucagonlike peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and the insulin secretory rate based on C-peptide levels by deconvolution. Results: Triglyceride levels increased similarly after oral and iv lipid; also, glucose and free fatty acid levels were similar in the two tests. Oral lipid elicited a clear insulin and C-peptide response, whereas no insulin or C-peptide responses were observed during iv lipid. Total and intact GIP and GLP-1 levels both increased after oral lipid administration but were not significantly altered after iv lipid. Conclusions: At matching triglyceride levels and with no difference in glucose and free fatty acid levels, oral lipid ingestion but not iv lipid infusion elicits a clear insulin response in association with increased GIP and GLP-1 concentrations. This may suggest that the incretin hormones also contribute to the islet response to noncarbohydrate nutrients.

KW - Administration, Oral

KW - Adult

KW - Area Under Curve

KW - Blood Glucose

KW - C-Peptide

KW - Emulsions

KW - Fatty Acids, Nonesterified

KW - Gastric Inhibitory Polypeptide

KW - Glucagon-Like Peptide 1

KW - Humans

KW - Incretins

KW - Infusions, Intravenous

KW - Insulin

KW - Male

KW - Phospholipids

KW - Soybean Oil

KW - Triglycerides

KW - Young Adult

U2 - 10.1210/jc.2011-0266

DO - 10.1210/jc.2011-0266

M3 - Journal article

C2 - 21593115

VL - 96

SP - 2519

EP - 2524

JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

SN - 0021-972X

IS - 8

ER -