251. Endothelin-1 Reduces Glucose Uptake in Human Skeletal Muscle In Vivo and In Vitro.
- Author
-
Shemyakin, Alexey, Salehzadeh, Firoozeh, Duque-Guimaraes, Daniella Esteves, Böhm, Felix, Rullman, Eric, Gustafsson, Thomas, Pernow, John, and Krook, Anna
- Subjects
ENDOTHELINS ,BLOOD sugar ,INSULIN resistance ,MUSCLE cells ,BLOOD flow ,VASODILATION ,THERAPEUTICS - Abstract
OBJECTIVE--Endothelin (ET)-1 is a vasoconstrictor and proin-flammatory peptide that may interfere with glucose uptake. Our objective was to investigate whether exogenous ET-1 affects glucose uptake in the forearm of individuals with insulin resistance and in cultured human skeletal muscle cells. RESEARCH DESIGN AND METHODS--Nine male subjects (aged 61 ± 3 years) with insulin resistance (M value <5.5 mg/kg/min or a homeostasis model assessment of insulin resistance index >2.5) participated in a protocol using saline infusion followed by ET-1 infusion (20 pmol/min) for 2 h into the brachial artery. Forearm blood flow (FBF), endothelium-dependent vasodilatation, and endothelium-independent vasodilatation were assessed. Molecular signaling and glucose uptake were determined in cultured skeletal muscle cells. RESULTS--ET-1 decreased forearm glucose uptake (FGU) by 39% (P < 0.05) after the 2-h infusion. ET-1 reduced basal FBF by 36% after the 2-h infusion (P < 0.05) and impaired both endothelium-dependent vasodilatation (P < 0.01) and endothelium-independent vasodilatation (P < 0.05). ET
A and ETB receptor expression was detected on cultured skeletal muscle cells. One-hour ET-1 incubation increased glucose uptake in cells from healthy control subjects but not from type 2 diabetic patients. Incubation with ET-1 for 24 h reduced glucose uptake in cells from healthy subjects. ET-1 decreased insulin-stimulated Akt phosphorylation and increased phosphorylation of insulin receptor substrate-1 serine 636. CONCLUSIONS--ET-1 not only induces vascular dysfunction but also acutely impairs FGU in individuals with insulin resistance and in skeletal muscle cells from type 2 diabetic subjects. These findings suggest that ET-1 may contribute to the development of insulin resistance in skeletal muscle in humans. [ABSTRACT FROM AUTHOR]- Published
- 2011
- Full Text
- View/download PDF