Since phosphorylation of FoxOs is primarily regulated by the growth factor-activated PI3K/Akt signaling pathway, we measured Akt phosphorylation, an indicator of Akt activation, after d-fenfluramine treatment. Similar to the effects on FoxOs, d-fenfluramine caused a rapid increase in phospho-Thr308-Akt and phospho-Ser473-Akt in the cerebral cortex, hippocampus, and striatum (Figure 2a). The level of Akt phosphorylation after 2-hr d-fenfluramine treatment was significantly higher than saline controls, but d-fenfluramine had no effect on the level of total Akt in the tested brain regions (Figure 2b).
