Fig. 3. Glucose induces de novo lipogenesis and lipid accumulation in contracting myotubes. (A) After 48 hours in serum-free medium containing 5 mM glucose (G5), cells were treated or not with 100 nM insulin for the last 24 hours. The lipogenesis rate from [2-¹⁴C]acetate (5 mM) was measured in the presence or absence of 25 mM glucose (G25) and/or 5 µM TOFA during the last 3 hours of culture. Results are the means±s.e.m. of 3-13 independent experiments. ^*P<0.05 compared with G5; ^**P<0.01 compared with the respective controls. (B) After a 24-hour treatment with 100 nM insulin or 25 mM glucose (G25), myotubes were stained with Oil Red-O to detect the presence of intracellular lipid droplets. Nuclei were counterstained with DAPI. Scale bar, 15 µm.