title: GLP-1 increases microvascular recruitment but not glucose uptake in human and rat skeletal muscle.
abstract: The insulinotropic gut hormone glucagon-like peptide-1 (GLP-1) has been proposed to have effects on vascular function and glucose disposal. However, whether GLP-1 is able to increase microvascular recruitment (MVR) in humans has not been investigated. GLP-1 was infused in the femoral artery in overnight-fasted, healthy young men. Microvascular recruitment was measured with real-time contrast-enhanced ultrasound and leg glucose uptake by the leg balance technique with and without inhibition of the insulinotropic response of GLP-1 by coinfusion of octreotide. As a positive control, MVR and leg glucose uptake were measured during a hyperinsulinemic-euglycemic clamp. Infusion of GLP-1 caused a rapid increase (P < 0.05) of 20 ± 12% (mean ± SE) in MVR in the vastus lateralis muscle of the infused leg after 5 min, and MVR further increased to 60 ± 8% above preinfusion levels by 60 min infusion. The effect was slightly slower but similar in magnitude in the noninfused contralateral leg, in which GLP-1 concentration was within the physiological range. Octreotide infusion did not prevent the GLP-1-induced increase in MVR. GLP-1 infusion did not increase leg glucose uptake with or without octreotide coinfusion. GLP-1 infusion in rats increased MVR by 28% (P < 0.05) but did not increase muscle glucose uptake. During the hyperinsulinemic clamp, MVR increased ∼40%, and leg glucose uptake increased 35-fold. It is concluded that GLP-1 in physiological concentrations causes a rapid insulin-independent increase in muscle MVR but does not affect muscle glucose uptake.
authors.affiliation: Section of Molecular Physiology, the August Krogh Centre, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark;
authors.forename: Kim A
authors.initials: KA
authors.lastname: Sjøberg
authors.forename: Jens J
authors.initials: JJ
authors.lastname: Holst
authors.forename: Stephen
authors.initials: S
authors.lastname: Rattigan
authors.forename: Erik A
authors.initials: EA
authors.lastname: Richter
authors.forename: Bente
authors.initials: B
authors.lastname: Kiens
mesh_terms: D000328:Adult; D000818:Animals; D002196:Capillaries / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D005765:Gastrointestinal Agents / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000000981:diagnostic imaging; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D015282:Octreotide / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014463:Ultrasonography
chemical_list: D005765:Gastrointestinal Agents; D052216:Glucagon-Like Peptide 1; D005947:Glucose; D015282:Octreotide
keywords: capillary recruitment; incretin hormones; insulin; microcirculation