title: Evidence for the involvement of vicinal sulfhydryl groups in insulin-activated hexose transport by 3T3-L1 adipocytes.
abstract: Following the differentiation of 3T3-L1 preadipocytes insulin acutely activates the rate of 2-deoxy-[1-14C]glucose uptake in the mature 3T3-L1 adipocyte by 15- to 20-fold. Phenylarsine oxide, a trivalent arsenical that forms stable ring complexes with vicinal dithiols, prevents insulin-activated hexose uptake in a concentration-dependent manner (Ki = 7 microM) but has no inhibitory effect on basal hexose uptake. 2,3-Dimercaptopropanol at a level nearly stoichiometric to that of phenylarsine oxide prevents or rapidly reverses the inhibition of hexose uptake; 2-mercaptoethanol, even in high stoichiometric excess over the arsenical, does not reverse inhibition of hexose uptake. When phenylarsine oxide is added after adipocytes have been fully activated by insulin, 2-deoxy-[1-14C]glucose uptake rate decays slowly at a rate corresponding to that caused by the withdrawal of insulin (t1/2 = 10 min). Using the same conditions under which phenylarsine oxide blocked activation, the Km for deoxyglucose uptake, the rate at which 125I-insulin became cell-associated, and the 125I-insulin binding isotherm for solubilized insulin receptor were not affected by phenylarsine oxide. These results support the transporter translocation model for insulin-activated hexose transport and implicate vicinal sulfhydryl groups in a post-insulin binding event essential for the translocation of glucose transporters to the plasma membrane.
mesh_terms: D019325:3-O-Methylglucose; D000255:Adenosine Triphosphate / Q000378:metabolism; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology*; D001693:Biological Transport, Active / Q000187:drug effects; D003571:Cytochalasin B / Q000378:metabolism; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006593:Hexokinase / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism; D051379:Mice; D011972:Receptor, Insulin / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D001152:Arsenicals; D003837:Deoxy Sugars; D007328:Insulin; D008757:Methylglucosides; C029341:oxophenylarsine; D019325:3-O-Methylglucose; D003571:Cytochalasin B; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D006593:Hexokinase; D011972:Receptor, Insulin