The pancreatic tumoral cell line AR42J is an in vitro model of exocrine pancreas but their exocrine function is abnormal. Some authors perform studies in AR42J cells treated with dexamethasone that favours their differentiation toward exocrine phenotype. It exists controversy over effects of dexamethasone on membrane fatty acid (FA) profile. We confirmed that dietary fat influences FA composition of pancreatic membranes (Yago et al.,2006; Martinez et al.,2004) and this influences the function. We also demonstrated that AR42J cells adapt their membranes after exposure to different FA in the medium (Audi et al.,2007).

AIM: To investigate if dexamethasone changes the adaptation of FA profile of cell membranes exposed to different FA and if dexamethasone affects the functional adaptation to different FA added. AR42J cells were incubated for 72h in presence or absence of dexamethasone in medium enriched with 18:1n-9 (AR42J-O) or with 18:2n-6 (AR42J-L). FA analysis was performed by gas-liquid chromatography. Amylase secretion in response to different doses of CCK-8 was assayed. In AR42J-O and AR42J-L cell membranes, there is an increase in monounsaturated-FA and decrease of n-3 polyunsaturated-FA in cells differentiated with dexamethasone compared with undifferentiated cells. Amylase secretion pattern is higher in differentiated vs. undifferentiated cells. Undifferentiated cells have different behaviour that differentiated cells against various doses of CCK-8.

In conclusion, dexamethasone influences the adaptation process of FA profile, which may alter several physiological functions. Supported by MEC (BFI2002-02772,AGL-2006-05005). Yago et al. JNutrBiochem (2006) 17:242-9. Martinez et al. Nutrition (2004) 20:536-41. Audi et al. ExpBiolMed (2007) 232:532-41.