Physical exercise enhances hepatic insulin signaling and inhibits phosphoenolpyruvate carboxykinase activity in diabetes-prone Psammomys obesus
| Autor: | Lea Langzam, Varda Barash, Joseph Meyerovitch, Y Shani, Yuval Heled, Yair Shapiro, Sanford R. Sampson, Daniel S. Moran |
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| Rok vydání: | 2004 |
| Předmět: |
Male
medicine.medical_specialty Endocrinology Diabetes and Metabolism medicine.medical_treatment Blotting Western Physical exercise Biology Eating chemistry.chemical_compound Endocrinology Physical Conditioning Animal Internal medicine Diabetes mellitus medicine Animals Insulin Phosphoenolpyruvate carboxykinase activity Kinase Proteins Tyrosine phosphorylation medicine.disease Precipitin Tests Insulin receptor Diabetes Mellitus Type 2 Liver chemistry Glucose-6-Phosphatase biology.protein Phosphoenolpyruvate Carboxykinase (GTP) Energy Metabolism Gerbillinae Phosphoenolpyruvate carboxykinase Signal Transduction |
| Zdroj: | Metabolism. 53:836-841 |
| ISSN: | 0026-0495 |
| DOI: | 10.1016/j.metabol.2004.02.001 |
| Popis: | We have shown that physical exercise enhances insulin sensitivity of skeletal muscle in diabetes-prone Psammomys-obesus. In this study, we examined the effect of physical exercise on the liver of these animals. Three groups of animals were exposed to a 4-week protocol; high-energy diet (CH), high-energy diet and exercising (EH), and low-energy diet (CL). Different groups were studied either in a fed state or after an overnight fast, 30 minutes after intraperitoneal (IP) injection of 1 U insulin. Hepatic phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) activity was measured. Insulin signaling response was examined after insulin injection in the fast state by analyzing tyrosine phosphorylation of insulin receptor (IR) and the association between insulin receptor substrate-1 (IRS-1) and IRS-2 with phosphatidylinositol 3 kinase (PI3-K). After 4 weeks, none of the EH animals became diabetic, whereas all the CH animals became diabetic. PEPCK activity in the fed state was higher in the CH group compared with the CL and EH groups (480 +/- 28 nmol/min/mg protein, 280 +/- 30 nmol/min/mg protein, and 208 +/- 13 nmol/min/mg protein, respectively) (P < .02). G6Pase activity was higher in the CH and EH groups compared with the CL group (261 +/- 54 nmol/min/mg protein, 251 +/- 34 nmol/min/mg protein, and 75 +/- 32 nmol/min/mg protein, respectively) (P < .01). After insulin administration in the fast state, tyrosine phosphorylation of IR and association of IRS-2 with PI3-K were higher in the EH and CL groups than in the CH group. We conclude that exercise improves in vivo hepatic insulin sensitivity in diabetes-prone Psammomys-obesus. |
| Databáze: | OpenAIRE |
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