Metabolism of D-[1-13C]fructose, D-[2-13C ]fructose, and D-[6-13C]fructose in rat hepatocytes incubated in the presence of H2O or D2O

Isolated hepatocytes from fed rats were exposed for 120 min to D-[1-C-13]fructose, D-[2-C-13]fructose, or D-[6-C-13]fructose in the presence of H2O or D2O. The identification and quantification of C-13-enriched metabolites (D-glucose, L-lactate) in the incubation medium and the measurement of their deuterated isotopomers indicated that the ketohexose was phosphorylated predominantly at the intervention of fructokinase and that the majority of the D-glyceraldehyde molecules generated from D-fructose 1-phosphate were further metabolized, e.g., after phosphorylation to D-glyceraldehyde 3-phosphate. It is proposed that the present procedure may help to further characterize the regulation of D-fructose metabolism in both hepatocytes and other cell types. (C) 2002 Elsevier Science (USA).