The D-glucose transporter is tissue-specific. Skeletal muscle and adipose tissue have a unique form of glucose transporter.

C Wang

doi:10.1016/s0021-9258(18)47782-4

Abstract

Using isotopic equilibration with [3H]D-glucose and measurement of D-glucose inhibitable cytochalasin B binding, I show that the erythrocytes of embryonic and newborn rats contain D-glucose transporters. On the basis of cytochalasin B binding and the time course of isotopic exchange, the number of transporters in rat embryonic erythrocytes is only 5% of that in human erythrocytes. Antibodies raised against the human erythrocyte glucose transporter were used as a probe to investigate the structural similarity between transporters. On this basis, the polypeptides of the glucose transporter of human erythrocytes and of embryonic rat erythrocytes are similar but not identical; in addition, certain antibodies showed similar reactivity toward the transporter of rat embryonic erythrocytes and that of rat brain. These antibodies, however, react with brain transporters 5 to 10 times better than with those of skeletal muscle and adipocytes suggesting that insulin responsive tissues may have a different type of glucose transporter. The cellular location of glucose transporters in skeletal muscle, determined by immunofluorescence, is on the plasma membrane or very close to the plasma membrane.

Highlights

Using isotopic equilibration with [3H]D-glucose and major differences in these two types of transporters may be measurement of D-glUCOSt?inhibitable cytochalasin B in the extentof glycosylation
Zation of glucose transporters is that insulin increases the Antibodiesraisedagainstthe human erythrocyte glucose transporterwere used as a probeto investigate the structuralsimilaritybetween transportersO. n this basis, the polypeptides of the glucose transporter of human erythrocytes andof embryonic rat erythrocytes are similar but not identical; in addition, certainantibodiesshowedsimilar reactivity towardthetransrate of glucose transport insome cells, notably adipocytes and skeletal muscle cells
The translocation hypothesis is supported by the evibrain.Theseantibodies, react with brain dence that insulin causes an increase in the V, of glucose transporters 5 to 10 times better than with those of transport with little effect on the K, for glucose (Vinten et skeletal muscle and adipocytes suggesting that insulin al., 1976).It should not be disregarded, that thereis responsivetissues may have a different type of glucosaereport (Whitesell and Abumrad, 1985) indicating that the transporter

Summary

Introduction

Using isotopic equilibration with [3H]D-glucose and major differences in these two types of transporters may be measurement of D-glUCOSt?inhibitable cytochalasin B in the extentof glycosylation. N this basis, the polypeptides of the glucose transporter of human erythrocytes andof embryonic rat erythrocytes are similar but not identical; in addition, certainantibodiesshowedsimilar reactivity towardthetransrate of glucose transport insome cells, notably adipocytes and skeletal muscle cells (for a review, see Simpson and Cushman, 1986). This effect does not require the synthesis ofnew transporters but appeartso involve the translocation of transporters from an intracellular storage site to theplasma membrane(Cushmanand Wardzala, 1980; Suzuki and Kono, porter of rat embryonic erythrocytes and that of rat 1980).

Methods

Results

Conclusion