Regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses (PubMed:28953886, PubMed:28846097, PubMed:28846098, PubMed:28846099, PubMed:23468844, PubMed:29046435). Binds to its receptor, GFRAL, and activates GFRAL-expressing neurons localized in the area postrema and nucleus tractus solitarius of the brainstem (PubMed:28953886, PubMed:28846097, PubMed:28846098, PubMed:28846099). It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitutes part of the 'emergency circuit' that shapes feeding responses to stressful conditions (PubMed:28953886). On hepatocytes, inhibits growth hormone signaling (By similarity). Homodimer; disulfide-linked (PubMed:29046435). Interacts with GFRAL; ligand of GFRAL which mediates GDF15 internalization and cellular signaling through interaction with RET (PubMed:28953886, PubMed:28846097, PubMed:28846098, PubMed:28846099). Highly expressed in placenta, with lower levels in prostate and colon and some expression in kidney (PubMed:9348093). Detected in plasma (at protein level) (PubMed:28572090, PubMed:29046435). Expression is up-regulated by obesity. Plasma levels are increased in children with concomitant heart disease and failure to thrive but not in children with heart disease and normal body weight. Belongs to the TGF-beta family.