Fig. 2.

Fructose oxidation and fructose-derived glutamate synthesis via TCA cycle. Adipocytes were exposed to 0.1, 0.5, 1, 2.5, 5, 7.5 or 10 mM fructose in a medium containing a baseline amount of 5 mM glucose from the initiation of differentiation for 8 days (differentiating adipocytes) or 16 days (differentiated adipocytes). 10 % of fructose was supplied as [U-¹³C₆]-fructose for a period of 48 h before harvest. Fructose oxidation was measured in differentiating adipocytes (a) and differentiated adipocytes (b) by the change Δ in the ¹³CO₂ released in the extracellular medium measured as a ratio of ¹³C/¹²C (replacement of ¹²C by ¹³C) in extracellular bi-carbonate. ¹³C Δ is a measure of the ratio of stable isotopes ¹³C:¹²C, reported in parts per thousand (per mil,  ‰). Extracellular release of [¹³C]-glutamate in differentiating adipocytes (c) and differentiated adipocytes (d) is expressed as a percentage of total glutamate released