Neurotrophic factor that enhances survival and morphological differentiation of dopaminergic neurons and increases their high-affinity dopamine uptake (By similarity). Essential for the development of the enteric nervous system, but appears dispensable for the development of the kidney and primary motor neuron. Homodimer; disulfide-linked. First expressed at 14 hours post-fertilization (hpf) in the ventral half of anterior somites and in intermediate mesoderm. Ventral somitic expression persists and extends more posteriorly over the next 12 hours. Expressed throughout the ventral trunk mesoderm and endoderm at 24 hpf. By 30 hpf, somitic expression ceases and by 36 hpf, expression becomes restricted to the endodermal cells forming the gut, with expression along the whole length of the developing gut tube at 72 hpf. Belongs to the TGF-beta family. GDNF subfamily.