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This Article Full Text Full Text (PDF) All Versions of this Article: 294/2/E380    most recent 00642.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Johnson, K. M. S. Articles by Cherrington, A. D. PubMed PubMed Citation Articles by Johnson, K. M. S. Articles by Cherrington, A. D.

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

Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee

Submitted 3 October 2007 ; accepted in final form 4 December 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 160 mg/dl. In addition, either saline (n = 6) or GLP-1 (1 pmol·kg^–1·min^–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.

dog; glucagon-like peptide-1; hepatic portal vein; portal signal