Immunocytochemical localization of fat/muscle-type glucose transporter (GLUT4) in the rat skeletal muscle: Effect of insulin treatment.

Abstract

Localization of fat/muscle-type glucose transporter (GLUT4) was examined in rat soleus muscle by immunofluorescence and immunogold labeling of frozen sections. Semithin and ultrathin frozen sections were stained with anti-peptide antibodies raised against the C-terminus of GLUT4. In the muscle sections from untreated and fasted animals, GLUT4 was concentrated intracellularly in the trans-Golgi and the trans-Golgi reticulum regions. GLUT4 was also found in vesicles and tubules near the plasma membrane. Insulin administration resulted in the appearance of the GLUT4 reactivity at the plasma membrane, while a significant amount of GLUT4 remained intracellularly in vesicles and tubules and also in the Golgi. These observations suggest that vesicles and tubules near the plasma membrane and in the trans-Golgi regions are reservoirs of intracellular GLUT4 and that fusion of these vesicles and tubules with the plasma membrane upon insulin stimulation is the mechanism to supply the plasma membrane with GLUT4.

Aquaporin Water Channels in the Kidney

“…In skeletal muscle cells and 3T3-L1 adipocytes, ample GLUT4 is present in the perinuclear region. Immunofluorescence and immunoelectron microscopy showed that GLUT4 is abundant in the Golgi apparatus and the trans-Golgi network [56]. Only a portion of intracellular GLUT4 is found in other vesicular compartments.…”

Introduction and Expression of Glucose Transporters in Pancreatic Acinar Cells by In Vivo Electroporation

“…Sections were incubated with one of anti-glucose transporter antibodies at room temperature for 1 hr. Anti-glucose transporter antibodies used were rabbit anti-GLUT1 (1:500 dilution) [26], rabbit anti-GLUT3 (1:1000 dilution) [16], rabbit anti-GLUT4 (1:500 dilution) [28], and rabbit anti-GLUT5 (1:500 dilution) [9]. After being washed with PBS, the sections were incubated with LRSC (lissamine rhodamine sulfonyl chloride)-labeled donkey anti-rabbit IgG (Jackson Immunoreseach, West Grove, PA, 1:200 dilution) as a secondary antibody at room temperature for 1 hr.…”

“…GLUT1 and GLUT2 are localized at the basolateral plasma membrane, whereas GULT5 is localized in the apical membrane in the kidney epithelial cells. Moreover, GULT4 resides in the intracellular compartments [4,19,28]. Upon insulin stimulation, it is recruited to the plasma membrane and serves in the uptake of glucose.…”

Mammalian Sugar Transporters:Their Localization and Link to Cellular Functions.

“…In skeletal muscle, an immunofluorescence study showed that GLUT4 resides intracellularly, especially around the nuclei, under basal conditions in the rat soleus muscle (75) (Fig.7). GLUT4 was shown to be localized in the triad (terminal cisternae and transverse tubules) and in sarcoplasmic tubules under basal conditions by immunolabeling of LR Whiteembedded human vastus lateralis muscle (16).…”

“…GLUT4 was shown to be localized in the triad (terminal cisternae and transverse tubules) and in sarcoplasmic tubules under basal conditions by immunolabeling of LR Whiteembedded human vastus lateralis muscle (16). By immunogold labeling of ultrathin frozen sections, GLUT4 was localized at the trans-Golgi reticulum region and in vesicles and tubules near the plasma membrane (62,75). Insulin stimulation induced an increase in GLUT4 density at the plasma membrane, although a significant amount of the transporter remained intracellularly.…”