(A) The amount of radioactivity in the serum (left) and liver (right) 20 min after an oral bolus of HFCS that contained U-[14C]-fructose tracer in wild-type (WT) (n = 4) and tumor-bearing APC−/− mice (n = 6). Radioactivity amount is presented as disintegrations per minute (DPM) per microliter (serum) or per microgram of protein input (liver). WT and APC−/− compared by Student’s t test, **P < 0.01. (B) Schematic depicting key enzymes and metabolites in glycolysis, fructolysis, and purine salvage pathways. Red indicates key fructose metabolites; blue indicates enzymes. Glu, glucose; Fruc, fructose; G6P, glucose 6-phosphate; FBP, fructose 1,6-bisphosphate; G3P, glyceraldehyde 3-phosphate; Pyr, pyruvate; F1P, fructose 1-phosphate; GA, glyceraldehyde; DHAP, dihydroxyacetone phosphate; ATP, adenosine triphosphate; ADP, adenosine diphosphate; AMP, adenosine monophosphate; IMP, inosine monophosphate; HK, hexokinase; PFK, phosphofructokinase; PK, pyruvate kinase; ALDOB, aldolase B; KHK, ketohexokinase; AMPD2, AMP deaminase 2. (C) Percent labeling of fructose 1-phosphate and (D) lactate following a 10-min ex vivo incubation with 10 mM U-[13C]-glucose, 10 mM U-[13C]-glucose with 10 mM fructose, 10 mM U-[13C]-fructose, and 10 mM U-[13C]-fructose with 10 mM glucose. The isotopic labeling of each metabolite is indicated by the M+# designation indicated in the legend where the # represents how many [12C] were replaced with [13C]. For example, the M+3 species for fructose 1-phosphate has the chemical formula 13C312C3H13O9P. n = 3 to 4 per group. Two-way ANOVA with Holm-Sidak post-test compared to the U-[13C]-glucose condition. *P < 0.05, ***P < 0.001, ****P < 0.0001, 13C Glu, U-[13C]-glucose; 13C Fru, U-[13C]-fructose. (E) Relative abundance of key metabolites in the adenine purine salvage pathway. Con (n = 14), HFCS (n = 9). Two-way ANOVA with Holm-Sidak post-test *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. All data represent means ± SEM.