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Effects of valinomycin on hexose transport and cellular ATP pools in mouse fibroblasts
Author(s) -
Yamanishi Kiyofumi
Publication year - 1984
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041190204
Subject(s) - valinomycin , chemistry , hexose , nigericin , biochemistry , ionophore , stimulation , dinitrophenol , extracellular , membrane potential , biophysics , biology , enzyme , membrane , endocrinology
The K + ionophore valinomycin at concentrations of 1 × 10 −8 M and over, stimulated 2‐deoxy‐D‐glucose (2DG) and 3‐O‐methylglucose (3OMG) uptake in Swiss 3T3 fibroblasts. The rate‐limiting step of 2DG uptake was transport rather than phosphorylation, in the control or valinomycin‐treated cells. Kinetic analysis showed that valinomycin increased the V max for 2DG uptake without change of the K m . The valinomycin‐stimulated 2DG uptake was insensitive to 10 μg/ml cycloheximide, and extracellular K + concentrations between 0.1 and 50 mM. On the other hand, valinomycin at the concentration of 1 × 10 −8 M and over, induced a rapid decrease in cellular ATP content, followed by stimulation of 2DG uptake and recovery of the ATP content. A similar relationship between the reduction of cellular ATP content and the subsequent stimulation of 2DG uptake was observed when the cells were treated not only with 2,4‐dinitrophenol and iodoacetic acid, but also with other monovalent cation ionophores or inhibitors of oxidative phosphorylation. These results suggest that valinomycin may posttranslationally stimulate hexose transport by increasing the number of functional carriers of hexose or changing their mobility, and the rapid decrease in cellular ATP pools by valinomycin may be a trigger of the stimulation of the hexose transport in Swiss 3T3 fibroblasts.