Alloxan action on glucose metabolism in cultured fibroblasts. I. Stimulation and inhibition of glucose utilization.

The influence of alloxan on mammalian cell glucose metabolism has been investigated using human diploid fibroblastic cells in culture. When cell monolayers were exposed to D-[14C]glucose, the presence of alloxan (0.31-1.87 mM) resulted initially in a dose-dependent enhancement of total cell glucose incorporation. This was observed within 2 min and declined by 6 min. After that time, alloxan inhibited glucose incorporation. When hexose transport was examined directly using glucose analogues, alloxan neither enhanced nor inhibited the uptake of 3-O-methylglucose or 2-deoxyglucose. Alloxan exerted no effect on cell permeability or cell viability. These results suggest that alloxan may directly influence cell glucose metabolism beyond the level of phosphorylation. The dual effect of alloxan on glucose incorporation may be related to the alloxan stimulation and subsequent inhibition of glucose-induced insulin release in pancreatic islets.