Menadione- and cyclic AMP-induced alteration of the ratio between D-[2-3H]glucose detritiation and phosphorylation in rat erythrocytes.

When rat erythrocytes are exposed to both dibutyryl-cyclic AMP and isobutylmethylxanthine, the rates of D-glucose phosphorylation and glycolysis are both markedly increased. On the contrary, menadione by increasing the flow rate through the pentose phosphate pathway, decreases the generation rate of triose phosphates from exogenous D-glucose. Yet, both procedures lead to a decrease in the production of 3HOH from D-[2-3H]glucose relative to its phosphorylation rate. It is proposed, therefore, that such a radioactive measurement should no more be considered as a reliable index of D-glucose phosphorylation, at variance with current practice.