The short-term presence of oleate or octanoate alters the phosphorylation status of Akt, AMPK, mTOR, CREB, and FoxO1 in liver of rainbow trout (Oncorhynchus mykiss)

We hypothesized that the presence of specific fatty acids modulate lipid metabolism in fish liver through changes in the phosphorylation status of proteins involved in cell signaling (Akt and mTOR) and cellular energy sensing (AMPK), and transcription factors (CREB and FoxO1). Therefore, we evaluated in pools of rainbow trout livers incubated for 3 h and 6 h at 15 °C in modified Hanks' medium containing 100 or 500 μM oleate or octanoate, the response of these proteins. Our data confirm, for the first time in fish, that treatment of rainbow trout liver with oleate or octanoate resulted in the modulation of phosphorylation status of proteins involved in cell signaling (increased Akt and mTOR) and energy sensing (decreased AMPK), and in transcription factors (decreased CREB and increased FoxO1). The changes in these proteins occurred at the same time that changes in the mRNA abundance of several genes involved in lipid metabolism suggesting enhanced lipogenic potential (increased mRNA abundance of FAS, SREBP1c, and PPARα) and decreased mitochondrial activity (decreased UCP2a mRNA abundance) allowing us to suggest a relationship between both processes.