Intraportally delivered GLP-1, in the presence of hyperglycemia induced via peripheral glucose infusion, does not change whole body glucose utilization.

Johnson KM, Edgerton DS, Rodewald T, Scott M, Farmer B, Neal D, Cherrington AD
Am J Physiol Endocrinol Metab. 2008 294 (2): E380-4

PMID: 18056788 · DOI:10.1152/ajpendo.00642.2007

After a meal, glucagon-like peptide-1 (GLP-1) and glucose levels are significantly greater in the hepatic portal vein than in the artery. We have previously reported that, in the presence of intraportal glucose delivery, a physiological increase of GLP-1 in the hepatic portal vein increases nonhepatic glucose uptake via a mechanism independent of changes in pancreatic hormone secretion. The aim of the present study was to determine whether intraportal glucose delivery is required to observe this effect. Experiments consisted of a 40-min basal period, followed by a 240-min experimental period, during which conscious 42-h fasted dogs received glucose peripherally to maintain arterial plasma glucose levels at approximately 160 mg/dl. In addition, either saline (n = 6) or GLP-1 (1; GLP-1, n = 6) was administered intraportally during the experimental period. As in the previous study, the presence of GLP-1 did not alter pancreatic hormone levels; however, in the present study, intraportal GLP-1 infusion did not result in an increase in whole body glucose utilization. This is despite the fact that arterial and hepatic portal vein GLP-1 levels were maintained at the same level as the previous study. Therefore, a physiological elevation of GLP-1 in the hepatic portal vein does not increase whole body glucose uptake when hyperglycemia is induced by peripheral glucose infusion. This indicates that a physiological increase in GLP-1 augments glucose utilization only when GLP-1 and glucose gradients conditions mimic the postprandial state.

MeSH Terms (13)

Animals Blood Glucose Dogs Enzyme-Linked Immunosorbent Assay Female Glucagon Glucagon-Like Peptide 1 Glucose Hyperglycemia Infusions, Intravenous Insulin Liver Circulation Male

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