Insulin-induced translocation of glucose transporters from post-Golgi compartments to the plasma membrane of 3T3-L1 adipocytes.

Abstract

Abstract. A semiquantitative method using immunocytochemistry on ultrathin cryosections and the protein A-gold technique was performed to study the effect of insulin on the cellular distribution of the glucose transporters in cultured 3T3-L1 adipocytes. In basal cells a substantial portion of the label was present in a tubulovesicular structure at the trans side of the Golgi apparatus, likely to represent the trans-Golgi reticulum, and in small vesicles present in the cytoplasm. Treatment with insulin induced a rapid translocation of transporters from the tubulovesicular structure to the plasma membrane. The transporter labeling of the plasma membrane increased three-fold and that of the tubulovesicular structure decreased by half. There was no effect of insulin on the degree of label in the small cytoplasmic vesicles. Removal of insulin from stimulated cells rapidly reversed the distribution of transporters to that seen in basal cells. This study thus provides the first morphological evidence for the occurrence of transporter translocation in insulin action and identifies for the first time the intracellular location of the responsive transporters.

Mechanisms and time course of impaired skeletal muscle glucose transport activity in streptozocin diabetic rats.

“…In the current study, we found that the difference between basal and insulin-stimulated PM GLUTI was highly significant (P < 0.005). The significance of GLUTi translocation in skeletal muscle could be the same suggested for adipose cells (56,(69)(70)(71)(72)(73): the translocation of GLUTi is probably distinct from that of GLUT4 and may reflect a more general and nonspecific insulin-induced redistribution of membrane proteins from the Golgi apparatus to the plasma membrane. However, our observation that the changes induced by insulin stimulation in CB binding and GLUT4 are parallel confirms that GLUT4 is quantitatively more important.…”

Hyperglycaemia-induced subcellular redistribution of GLUT1 glucose transporters in cultured human term placental trophoblast cells

“…The GLUT1 distribution was quantified by counting immunogold particles in ultrathin sections according to a standard procedure [22]. Three grids among 15±20 from each trophoblast preparation (n = 5) were selected on the basis of good morphology at a magnification of x 700.…”

Pattern of glucose transporter (Glut 1) expression in embryonic brains is related to maturation of bood‐brain barrier tightness

“…partment can occur. While the molecular identity of the BBB-GT has been firmly established (Ezaki and Kono, 1984;Ezaki et al, 1986;Blok et al, 1988;Gerhart et al, 1989;Boado and Pardridge, 1990;Harik et al, 1990), little is kfiown about its developmental expression. In a recent paper (Sivitz et al, 1989) described a bisphasic change in magnitude of Glut 1 expression in developing brains with a dramatic decrease present immediately postbirth.…”