Synergistic activation of 2-deoxy-d-glucose uptake in rat and murine peritoneal macrophages by human macrophage colony-stimulating factor-stimulated coupling between transport and hexokinase activity and phorbol-dependent stimulation of pentose phosphate-shunt activity

1. Transport and accumulation of 2-deoxy-D-glucose (2dGlc) in rat and murine peritoneal macrophages were investigated by using C-1-3H-labelled and C-2,6-3H-labelled 2dGlc. 2. There was active accumulation of both C-1- and C-2,6-labelled 2dGlc by quiescent rat and murine macrophages via a phloretin-inhibitable transport system. 3. The rate of uptake and accumulation of 2dGlc (C-1 label) was increased by exposure to human macrophage colony-stimulating factor (mCSF-1) (1000 units/ml) in both murine and rat macrophages. This indicates that mCSF-1 enhances coupling between hexokinase activity and glucose transport at the endofacial surface of the transporter. 4. Phorbol 12-myristate 13-acetate (‘phorbol’) at 40 nM stimulated 2dGlc in rat macrophages entirely by increasing the C-2,6 label uptake. This indicates that phorbol stimulates 2dGlc uptake mainly by increasing the activity of the pentose phosphate pathway. 5. Simultaneous exposure to phorbol and mCSF-1 stimulates 2dGlc uptake to a greater extent than found with either phorbol or mCSF-1 alone. This result is explained by a simultaneous enhancement of pentose phosphate-pathway activity and of hexokinase activity acting at the endofacial surface of the cell membrane. The dual activation of these serial processes coupled to the loss of the reaction products of the pentose phosphate-shunt pathway from the cells in the form of reactive oxygen intermediates, protons and CO2 could explain the synergistic action of phorbol and mCSF-1 in activation of sugar transport in macrophages.