Effects of Sodium Butyrate, D-Glucose, and Dibutyryl cAMP On Glut 4 Mediated Insulin-Stimulated Transport in Cultured Rat Skeletal Muscle Cells
Loading...
Authors
Caruana, Crystal M.
Issue Date
1992
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
The effects of sodium butyrate, D-glucose, and dibutyryl cAMP on
insulin-stimulated glucose transport in rat skeletal muscle cells (L-6 line)
previously transfected with wild type GLUT 4 transporter protein were
studied. 2-deoxy[3H]glucose (a glucose analog) uptake was measured in
the presence of insulin, dibutryl cAMP, and D-glucose to investigate two
basic problems.
First, attempts were made to select a cell line transfected with wild
type GLUT 4 (lRGT lines) that had insulin-stimulated 2-deoxy[3H]glucose
transport that was at or near the level of the 243-6 line. 243-6 cells have a
mutated form of the GLUT 4 protein and are overexpressors of GLUT 4
and 2-deoxy[3H]glucose insulin-stimulated transport. Incubation with
sodium butyrate was used to enhance GLUT 4 mediated insulin-stimulated
2-deoxy[3H]glucose transport in IRGT lines that were chosen to
be potential overexpressors of the protein. Increased transport was seen in
some cell lines treated with sodium butyrate. GLUT 4 expression was
measured by SD5-P AGE and immunoblotting using RBI, a GLUT 4 specific
antibody, and I25I-labelled protein A. Increased membraneous expression
of GLUT 4 in some cell lines was also observed. Enhanced
2-deoxy[3H]glucose transport was not accompanied by the expected
increased membraneous expression of GLUT 4. It is proposed that sodium
butyrate affects another mechanism of insulin stimulated glucose
transport instead of GLUT 4.
Second, the effects of glucose on insulin-stimulated transport were
investigated. Dibutryl cAMP inhibited 2-deoxy[3H]glucose insulinstimulated
transport. D-glucose reversed this inhibitory effect only in cells
that contained GLUT 4. It was concluded that D-glucose interferes with
normal mechanisms of dibutryl cAMP which have been shown
previously to impede transporter activation through kinase activity. Glucose
may reverse or prevent this activity thereby reducing cAMP's inhibitory
effect.
Description
iv, 34 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.