Acute effects on insulin, thyroid hormone, and cellular stress on glucose transporter mRNA in rat skeletal muscle / by James Edward de Venté.
| Author/creator | De Venté, James Edward author. |
| Other author | Dohm, G. Lynis, degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 1992. |
| Description | v, 98 leaves : illustrations ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The specific aims of this study were to: 1. investigate the acute effects of insulin on skeletal muscle GLUT-4 expression in a two and five hour rat hindlimb perfusion; 2. investigate the effects of thyroid hormones on GLUT-4 mRNA levels in skeletal muscle; 3. investigate the effects of the cellular stress involved in perfusion itself on skeletal muscle GLUT-1 and GLUT-4 mRNA levels. A rat hindlimb perfusion model was employed in this study to observe the direct hormonal effects of insulin and thyroid hormone independent of any secondary responses due to the metabolic and/or endocrine factors induced by these hormones in vivo. Herein I report that: 1. Neither two nor five-hour insulin perfusions have any apparent effect on GLUT-4 mRNA or protein levels in any of the muscle types assayed with the exception of red vastus. A 49% decrease in GLUT-4 was observed in the red vastus with two hours of insulin perfusion. 2. Ten days of thyroid hormone treatment generated 88% and 51% increases in GLUT-4 mRNA content in rat gastrocnemius and soleus, respectively. 3. Pour hours of thyroid hormone perfusion had no statistical effect on GLUT-4 mRNA levels. However, modest non-statistically significant increases in GLUT-4 mRNA were observed in every muscle group assayed. This trend was most apparent in the red fiber types (soleus 18% and red vastus 30%). 4. Increases of 150%-1080% in GLUT-1 mRNA content and 27%-144% in GLUT-4 mRNA content were observed when perfused muscles were compared to non-perfused muscles. This finding suggests that the act of perfusion itself has a dramatic effect on skeletal muscle GLUT-1 and more moderate effect on GLUT-4 mRNA content. In light of these results, I propose that: 1. insulin has no acute effects on skeletal muscle GLUT-4 mRNA or protein expression; 2. thyroid hormone increases skeletal muscle GLUT-4 mRNA in vivo and this effect may be direct; and, 3. the cellular stress involved in the act of perfusion induces a dramatic increase in the level of Glut-1 mRNA and a more moderate increase in the level of GLUT-4 mRNA. |
| General note | Submitted to the faculty of the Department of Biology. |
| General note | Advisor: G. Lynis Dohm |
| Dissertation note | M.S. East Carolina University 1992 |
| Bibliography note | Includes bibliographical references (leaves 88-93). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
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