Abstract
We studied the expression of the glucose transporter GLUT 4 in the soleus and red gastrocnemius muscles from obese, diabetic (fa/fa) Zucker rats compared to their lean littermates (Fa/-), with and without treatment with the antidiabetic drug metformin. In the untreated groups of rats, the GLUT 4 content in a crude membrane fraction of both the soleus and the red gastrocnemius muscles were significantly lower in the obese (fa/fa) rats (3.46 +/- 0.28 vs. 6.04 +/- 0.41, p <0.001 and 6.0 +/- 0.24 vs. 9.1 +/- 0.48, p <0.0001, respectively). Differences in GLUT 4 expression in soleus muscle from the same rats were confirmed by quantitative immunofluorescence microscopy, and the results were significantly correlated with the results obtained from quantitative immunoblotting (rho = 0.70, p <0.0005). The decreased expression of GLUT 4 in fa/fa rats could contribute to the well-established insulin resistance in skeletal muscle of these animals. After 4 weeks of treatment with metformin, weight gain was not affected in either the diabetic (fa/fa) rats or the lean (Fa/-) rats. Improvement of glucose homeostasis by metformin was not associated with normalization of the GLUT 4 expression in the skeletal muscles studied, indicating (1) that the decreased GLUT 4 expression is not directly related to hyperinsulinaemia and diabetes mellitus and (2) that metformin does not normalize the expression of GLUT 4 in skeletal muscle of the diabetic (fa/fa) Zucker rats.
| Original language | English |
|---|---|
| Journal | Diabetologia |
| Volume | 36 |
| Issue number | 6 |
| Pages (from-to) | 481-6 |
| Number of pages | 6 |
| ISSN | 0012-186X |
| Publication status | Published - 1993 |
Keywords
- Animals
- Biological Markers
- Blood Glucose
- Cell Membrane
- Diabetes Mellitus
- Diabetes Mellitus, Type 1
- Fructosamine
- Hexosamines
- Immunoblotting
- Male
- Metformin
- Monosaccharide Transport Proteins
- Muscles
- Obesity
- Rats
- Rats, Zucker
