Glucose inhibits cellular ascorbic acid uptake by fibroblasts in vitro

It has been suggested earlier that the local deficiency of ascorbic acid in tissues could be responsible for development of various angiopathies in diabetes. Hyperglycemia is one of the factors which could contribute considerably to the development of local ascorbic acid deficiency. Therefore, the effect of glucose on uptake of L-[1-14C] ascorbic acid by fibroblasts was studied in vitro. The data clearly show that ascorbic acid uptake is inhibited instantly by glucose in a concentration dependent fashion. The results support the contention that local ascorbic acid deficiency in tissues could be a natural consequence of hyperglycemia of whatever cause. The rate of ascorbic acid uptake under various conditions suggests that additional supplements of ascorbic acid might be helpful to individuals in averting deleterious effects of hyperglycemia on tissue ascorbic acid supply.