Effects of acute α2-blockade on insulin action and secretion in humans
| Autor: | Amalia Gastaldelli, Anna Maria Sironi, Ele Ferrannini, Pierre Rosenzweig, Demetrio Ciociaro, Andrea Natali, G Sanna, Alfredo Quiñones Galvan |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Adult
Blood Glucose Male medicine.medical_specialty Indoles Epinephrine Physiology Endocrinology Diabetes and Metabolism medicine.medical_treatment Biology Oxygen Consumption Physiology (medical) Internal medicine Insulin Secretion medicine Humans Insulin Adrenergic alpha-Antagonists Pancreatic hormone Analysis of Variance C-Peptide Imidazoles Calorimetry Indirect Lipid metabolism Adrenergic alpha-2 Receptor Antagonists Blockade Kinetics Endocrinology Hyperglycemia Glucose Clamp Technique Catecholamine Alpha-2 adrenergic receptor Thermogenesis medicine.drug |
| Zdroj: | Europe PubMed Central |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.1998.274.1.e57 |
| Popis: | We tested whether acute α2-blockade affects insulin secretion, glucose and fat metabolism, thermogenesis, and hemodynamics in humans. During a 5-h epinephrine infusion (50 ng ⋅ min−1 ⋅ kg−1) in five volunteers, deriglidole, a selective α2-receptor inhibitor, led to a more sustained rise in plasma insulin and C-peptide levels (+59 ± 14 vs. +28 ± 6, and +273 ± 18 vs. +53 ± 14 pM, P < 0.01 vs. placebo) despite a smaller rise in plasma glucose (+0.90 ± 0.4 vs. +1.5 ± 0.3 mM, P < 0.01). Another 10 subjects were studied in the postabsorptive state and during a 4-h hyperglycemic (+4 mM) clamp, coupled with the ingestion of 75 g of glucose at 2 h. In the postabsorptive state, hepatic glucose production, resting energy expenditure, and plasma insulin, free fatty acid (FFA), and potassium concentrations were not affected by acute α2-blockade. Hyperglycemia elicited a biphasic rise in plasma insulin (to a peak of 140 ± 24 pM), C-peptide levels (1,520 ± 344 pM), and insulin secretion (to 410 ± 22 pmol/min); superimposed glucose ingestion elicited a further twofold rise in insulin and C-peptide levels, and insulin secretion. However, α2-blockade failed to change these secretory responses. Fasting blood β-hydroxybutyrate and glycerol and plasma FFA and potassium concentrations all declined with hyperglycemia; time course and extent of these changes were not affected by α2-blockade. Resting energy expenditure (+25 vs. +16%, P < 0.01) and external cardiac work (+28% vs. +19%, P < 0.01) showed larger increments after α2-blockade. We conclude that acute α2-blockade in humans 1) prevents epinephrine-induced inhibition of insulin secretion, 2) does not potentiate basal or intravenous- or oral glucose-induced insulin release, 3) enhances thermogenesis, and 4) increases cardiac work. |
| Databáze: | OpenAIRE |
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