Abstract

Evolution of CO2 from labelled glucose microinjected into frog oocytes in vivo may be ascribed to the pentose-P pathway, as measured by radioactive CO2 production from [1-14C] and [6-14C]glucose. Coinjection of NADP+ and [14C]glucose significantly stimulated 14CO2 production. The effect depends on the amount of NADP+ injected, half maximal stimulation being obtained at 0.13 mM. The increase in CO2 production was also observed with microinjected glucose-1-P, glucose-6-P or fructose-6-P used as substrates. Phenazine methosulfate, mimicked the effects of NADP+. A high NADPH/NADP+ ratio of 4.3 was found in the cells, the intracellular concentration of NADP+ being 19 ?M. Copyright (C) 1999 Federation of European Biochemical Societies.