Document Detail

Phenylarsine oxide stimulates hexose transport in 3T3-L1 adipocytes by a mechanism other than an increase in surface transporters.
MedLine Citation:
PMID:  2643384     Owner:  NLM     Status:  MEDLINE    
Phenylarsine oxide (PAO) has been shown to exert a biphasic effect on glucose transport in 3T3-L1 adipocytes. At 10 microM, PAO activates transport threefold, but at higher concentrations an inhibition of transport is observed. In this paper we report a procedure for the subcellular fractionation of these cells which we use to examine the distribution of glucose transporters following PAO challenge. Quantitative immunoblotting showed that the glucose transporter content of the plasma membrane fraction increased with increasing PAO concentrations; a parallel increase in another insulin-responsive protein, the transferrin receptor, also occurred. However, cell-surface labeling procedures for the glucose transporter and transferrin receptor showed that PAO actually decreased the cell-surface concentrations of these proteins; the basis of this discrepancy may be that in the presence of PAO, intracellular vesicles containing these proteins associate with the plasma membrane, but do not fuse with it. The possibility that PAO modulated transport by direct interaction with the glucose transporter was investigated by examining the effects of PAO on transport in both erythrocytes and a reconstituted system of purified erythrocyte transporter in lipid vesicles. PAO was without effect on the rate of transport in these systems. The hypothesis that the stimulatory effect of PAO on transport might be due to the activation of the insulin receptor kinase activity was examined by assessing the phosphotyrosine content of the receptor and other proteins using anti-phosphotyrosine antibodies. PAO alone caused no detectable increase in receptor phosphotyrosine content. However, the combination of PAO and insulin led to the tyrosine phosphorylation of two proteins of Mr 68,000 and 57,000 which were not detected in cells treated with either PAO or insulin, and an increased phosphotyrosine content of proteins of Mr 95,000 and 165,000 when compared to cells treated with insulin alone.
G W Gould; G E Lienhard; L I Tanner; E M Gibbs
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Archives of biochemistry and biophysics     Volume:  268     ISSN:  0003-9861     ISO Abbreviation:  Arch. Biochem. Biophys.     Publication Date:  1989 Jan 
Date Detail:
Created Date:  1989-02-15     Completed Date:  1989-02-15     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0372430     Medline TA:  Arch Biochem Biophys     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  264-75     Citation Subset:  IM    
Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03756.
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MeSH Terms
Adipose Tissue / drug effects,  metabolism*
Arsenicals / pharmacology*
Cell Membrane / metabolism
Cells, Cultured
Insulin / pharmacology
Monosaccharide Transport Proteins / metabolism*
Receptors, Transferrin / drug effects,  metabolism
Grant Support
Reg. No./Substance:
0/Arsenicals; 0/Monosaccharide Transport Proteins; 0/Receptors, Transferrin; 11061-68-0/Insulin; 637-03-6/oxophenylarsine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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