Non-metabolized non-toxic methyl FFA do not elicit ER stress. INS-1E cells were exposed to control (C), palmitate (0.5 mM, P) or methyl-palmitate (0.5 mM, MeP) at 11 mM glucose. After 72 hours, the percentage of apoptotic cells was determined; n=4–5 (left). mRNA expression of ER stress markers was analyzed after 24 hours by real-time PCR and normalized for the housekeeping gene GAPDH; n=4. *P<0.05, **P<0.01 vs control.