Dose Dependent Effects of Fructose and Glucose on de novo Palmitate and Glycerol Synthesis in an Enterocyte Cell Model.

SCOPE Fructose exacerbates post-prandial hypertriacylglycerolaemia. This may be partly due to increased enterocyte de novo lipogenesis (DNL). It is unknown whether this is concentration-dependent or whether fructose has a greater effect on lipid synthesis than glucose. The dose-dependent effects of fructose and glucose on DNL and de novo triacylglycerol (TAG)-glycerol synthesis were investigated in an enterocyte model; Caco-2 cells. METHODS AND RESULTS Caco-2 cells were treated for 96h with 5mM, 25mM or 50mM fructose or glucose, or 12.5mM fructose/12.5mM glucose mix. DNL was measured following addition of [13 C2 ]-acetate to apical media. In separate experiments, [13 C6 ]-fructose and [13 C6 ]-glucose were used to measure DNL and de novo TAG-glycerol synthesis. DNL from [13 C2 ]-acetate was detected following all treatments, with greater amounts in intracellular than secreted (media) samples (all P <0.05). DNL from [13 C6 ]-fructose and [13 C6 ]-glucose was also measurable. Intracellular synthesis was concentration-dependent for both glucose and fructose tracers (P = 0.003, P = 0.034, respectively) and was higher with 25mM glucose than 25mM fructose (P = 0.025). DNL from fructose and glucose was <1%, but up to 70% of de novo TAG-glycerol was synthesised from glucose or fructose. CONCLUSION Fructose is not a major source of DNL in Caco-2 cells but contributes substantially to de novo TAG-glycerol synthesis. This article is protected by copyright. All rights reserved.