The mechanism of action of GDF-15 is not fully understood, although it was shown to block noradrenaline (norepinephrine)-induced myocardial hypertrophy by inhibiting the phosphorylation of EGFR (epidermal growth factor receptor) and the downstream kinases Akt and ERK (extracellular-signal-regulated kinase) 1/2 [5]. Here, EGFR is linked to cardiac hypertrophy.