Hypocaloric diet reduces exercise-induced alpha 2-adrenergic antilipolytic effect and alpha 2-adrenergic receptor mRNA levels in adipose tissue of obese women
| Autor: | Max Lafontan, Michel Berlan, Nathalie Viguerie, F. Marion-Latard, J. Hejnova, Hana Suljkovicova, Corinne Lefort, Vladimir Stich, Dominique Langin |
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| Rok vydání: | 2002 |
| Předmět: |
Adult
Glycerol medicine.medical_specialty Microdialysis Sympathetic nervous system Adrenergic receptor Diet Reducing Endocrinology Diabetes and Metabolism Clinical Biochemistry Adipose tissue Stimulation Physical exercise Fatty Acids Nonesterified Biochemistry Endocrinology Phentolamine Receptors Adrenergic alpha-2 Internal medicine Abdomen Receptors Adrenergic beta medicine Humans Lactic Acid Obesity RNA Messenger Exercise Chemistry Biochemistry (medical) Osmolar Concentration medicine.anatomical_structure Adipose Tissue Regional Blood Flow Catecholamine Female Energy Intake Extracellular Space medicine.drug |
| Zdroj: | The Journal of clinical endocrinology and metabolism. 87(3) |
| ISSN: | 0021-972X |
| Popis: | Previous investigations have shown that alpha 2-adrenoceptor (alpha 2-AR) stimulation blunts lipid mobilization during physiological activation of the sympathetic nervous system promoted by exercise in sc abdominal adipose tissue (SCAAT) in obese men. To investigate the effect of a low calorie diet (LCD) on the alpha 2-adrenergic responsiveness and on the expression of alpha 2-AR and beta 2-adrenoceptor (beta 2-AR) in SCAAT, 11 obese women (weight: 99.1 +/- 4.6 kg; body mass index: 34.3 +/- 1.1 kg/m(2)) received a 12-wk diet providing 500 kcal/d less than their usual diet. The exercise-induced alpha 2-adrenergic antilipolytic effect was investigated in SCAAT before and at the end of LCD. Changes in extracellular glycerol concentration and local blood flow were measured in SCAAT during a 45-min exercise bout (50% of heart rate reserve) using a control microdialysis probe and a probe supplemented with the alpha2-AR antagonist phentolamine. SCAAT biopsies were performed for determination of mRNA levels using RT-competitive PCR. Plasma catecholamine responses to exercise bout were not different before and at the end of LCD. Before LCD, the exercise-induced increase in extracellular glycerol concentration was potentiated by phentolamine supplementation, while this potentiating effect of the alpha-antagonist was not observed at the end of LCD. No changes were observed for beta 2-AR and hormone-sensitive lipase mRNA levels, while alpha 2-AR mRNA level was significantly decreased in adipose tissue during LCD. These findings show that alpha 2-AR-mediated antilipolytic action is reduced by a moderate hypocaloric diet and that down-regulation of alpha 2-AR mRNA levels may participate in the decrease of the alpha 2-adrenergic effect revealed by microdialysis. |
| Databáze: | OpenAIRE |
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