Glucose transport in fibroblasts is unaffected by polyamines

Abstract

Objective Wound healing is characterized by a net increase in glucose utilization in wound tissues. The mediators involved in this process remain largely unknown. Because polyamines are known to stimulate d-glucose uptake in brush-border membrane vesicles, we investigated whether or not they stimulated sugar uptake in confluent cultured fibroblasts. Methods Cells (at a quiescent or growing state) were incubated for 1 h with various concentrations (0.5–4 mM) of putrescine, spermine, or spermidine or for a range of times (30 min to 3 h) with 2 mM of these same polyamines. Cultures were then incubated for 5 min at +37°C with 2-deoxy- d-[1- 3H] glucose. Results Polyamines were found to have no action on sugar uptake in any of the experimental configurations. Conclusion These data suggest that polyamines have no effect in cell types in which glucose uptake is mediated by a passive facilitated diffusion process (energy independent). This contrasts with results obtained with cells in which sugar uptake is dependent on adenosine triphosphate. Even if this model does not reflect the complexity of wound healing, these negative results are nevertheless important because they suggest that the arginine- and ornithine-mediated effects on wound healing are not related to a polyamine-mediated increase in glucose transport in fibroblasts.