Insulin does not regulate glucose transport and metabolism in human endothelium
| Autor: | Michaela Artwohl, Clemens Fürnsinn, Sabina Baumgartner-Parzer, Georg Rainer, B. Brunmair, Nicole Huttary, Angelika Freudenthaler, E. M. Porod, T. Hölzenbein |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
medicine.medical_specialty
Nitric Oxide Synthase Type III Endothelium Glucose uptake medicine.medical_treatment Myocytes Smooth Muscle Clinical Biochemistry Glucose Transport Proteins Facilitative Biochemistry chemistry.chemical_compound Internal medicine medicine Humans Hypoglycemic Agents Insulin Phosphorylation Glycogen synthase Cells Cultured biology Glycogen Glucose transporter Endothelial Cells General Medicine Endothelial stem cell Insulin receptor Glucose Endocrinology medicine.anatomical_structure chemistry biology.protein |
| Zdroj: | European Journal of Clinical Investigation. 37:643-650 |
| ISSN: | 1365-2362 0014-2972 |
| DOI: | 10.1111/j.1365-2362.2007.01838.x |
| Popis: | BACKGROUND: Although endothelial cells express insulin receptors, it is controversially discussed whether the endothelium represents an insulin-responsive tissue. Since available data are primarily restricted to animal endothelial cells, this study tested (i) whether insulin affects glucose metabolism in human endothelium; (ii) whether insulin sensitivity is different in micro- versus macrovascular endothelial cells; and (iii) whether glucose concentration in the incubation medium affects the cells' response to insulin. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs), human adult saphenous vein endothelial cells (HAVECs), human aortic endothelial cells (HAEC), and human retinal endothelial cells (HRECs) as well as human smooth muscle cells were incubated with/without insulin (0.3 nmol L(-1) or 1 micromol L(-1)). Glucose transport, glycogen synthesis, glycogen content, lactate release, and expression of phospho-Akt, Akt, and endothelial nitric oxide synthase (eNOS) were determined. RESULTS: In HUVECs and HRECs, insulin (1 micromol L(-1)) increased (P < 0.05) eNOS expression by ~70% and doubled Akt phosphorylation, but the latter was by far more pronounced in human smooth muscle cells (+1093 +/- 500%, P < 0.05). In human smooth muscle cells, insulin (1 micromol L(-1)) stimulated glycogen synthesis by 67 +/- 11% (P < 0.01). In human micro- (HRECs) and macrovascular endothelial cells (HUVECs, HAVECs and HAECs), insulin, however, failed to stimulate glucose transport, glycogen synthesis, glycogen content, or lactate release under various conditions, i.e. after glucose deprivation or in medium with normal (5.5 mmol L(-1)) or high glucose (30 mmol L(-1)). CONCLUSIONS: Insulin stimulated glycogen synthesis and Akt phosphorylation in human smooth muscle cells. In human micro- and macrovascular endothelial cells, insulin, however, failed to affect glucose uptake and metabolism under all experimental conditions applied, whereas it increased Akt phosphorylation and eNOS expression. |
| Databáze: | OpenAIRE |
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