Glucose transport in murine macrophages: <i>in vitro</i> characterization of the monosaccharide transport system of the thioglycollate-elicited mouse peritoneal macrophage.

Abstract

Abstract The glucose transport system of the cultured, thiogly-collate-elicited mouse peritoneal macrophage was characterized in detail and shown to exhibit properties that satisfy the criteria for facilitated diffusion systems. The affinities of various monosaccharides for the system (expressed as Ks, the concentration of sugar at which the velocity of uptake is 50% of the maximum) were found to be: 2-deoxy-D-glucose, 3.6 mM; D-glucose, 11.7 mM; 3-O-methyl-D-glucose, 15.2 mM; L-arabinose, 111.5 mM; and L-glucose, &amp;gt;2.8 M. Competition of the above sugars with 3-O-methyl-glucose for the macrophage glucose carrier was also demonstrated, with the degree of competition reflecting the order of affinity given above. Saturation kinetics were observed with 3-O-methyl-glucose, the maximum uptake velocity being 20.3 nmoles/(μl cell water-min). The dipping method utilized for these studies represents an improvement on previously described rapid sampling techniques utilizing cells cultured on glass coverslips, allowing easier manipulation of the cover-slips, identical handling of coverslips from more than one treatment group and more rapid introduction of new medium to the surface of the monolayer. The latter property allows a more accurate determination of initial transport rates than previously available techniques. The methods and results described in this paper lay the groundwork for further studies on hormone effects on glucose transport and metabolism in the immunologically important macrophage.