Lipoic acid reduces glycemia and increases muscle GLUT4 content in streptozotocin-diabetic rats

Khamaisi, Mogher; Potashnik, Ruth; Tirosh, Amir; Demshchak, Eran; Rudich, Assaf; Trischler, Hans; Wessel, Klus; Bashan, Nava

« Previous Next »Metabolism - Clinical and Experimental
Volume 46, Issue 7 , Pages 763-768, July 1997

Lipoic acid reduces glycemia and increases muscle GLUT4 content in streptozotocin-diabetic rats☆

Mogher Khamaisi
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Ruth Potashnik
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Amir Tirosh
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Eran Demshchak
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Assaf Rudich
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Hans Trischler
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Klus Wessel
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany
Nava Bashan
- Address reprint requests to Nava Bashan, PhD, Department of Clinical Biochemistry, Faculty of Health sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
- ASTA Medica, Frankfurt, Germany

Received 22 July 1996; accepted 15 January 1997.

Abstract

Alpha lipoic acid (lipoate [LA]), a cofactor of α-ketodehydrogenase, exhibits unique antioxidant properties. Recent studies suggest a direct effect of LA on glucose metabolism in both human and experimental diabetes. This study examines the possbility that LA positively affects glucose homeostasis in streptozotocin (STZ)-induced diabetic rats by altering skeletal muscle glucose utilization. Blood glucose concentration in STZ-diabetic rats following 10 days of intraperitoneal (IP) injection of LA 30 mg/kg was reduced compared with that in vehicle-treated diabetic rats [495 ± 131 v 641 ± 125 mg/dL in fed state, P = .003, and 189 ± 48 v 341 ± 36 mg/dL after 12-hour fast, P = .001). No effect of LA on plasma insulin was observed. gastroenemius muscle crude membrane GLUT4 protein was elevated both in control and in diabetic rats treated with LA by 1.5- and 2.8-fold, respectively, without significant changes in GLUT4 mRNA levels. Gastroenemius lactic acid was increased in diabetic rats (19.9 ± 5.5 v 10.4 ± 2.8 μmol/g muscle, P < .05 v nondiabetic rats), and was normal in LA-treated diabetic rats (9.1 ± 5.0 μmol/g muscle). Insulin-stimulated 2-deoxyglucose (2 DG) uptake into isolated soleus muscle was reduced in treatment prevented this reduction, resulting in insulin-stimulated glucose uptake comparable to that of nondiabetic animals. These results suggest that daily LA treatment may reduce blood glucose concentrations in STZ-diabetic rats by enhancing muscle GLUT4 protein content and by increasing muscle glucose utilization.

No full text is available. To read the body of this article, please view the PDF online.