Fig. 1

Insulin protected high-glucose- or palmitate-induced INS-1 cell apoptosis via down-regulation of Nodal–ALK7–p-Smad3 expression. INS-1 cells were cultured in serum free medium and treated with medium alone (Control), or with 30 mM glucose (HG) or 0.4 mM palmitate (Pal) for 24 h (with or without 100 nM insulin) a: Cell lysates were subjected to western blot analysis using relevant antibodies as indicated. b: Bar graphs represent densitometry analysis, data were normalized to control and expressed as mean ± SE. n = 3. **, p < 0.01. t-Smad3: total Smad3; t-caspase-3: total caspase-3