Neurotrophic factor that enhances survival and morphological differentiation of dopaminergic neurons and increases their high-affinity dopamine uptake. Homodimer; disulfide-linked. From stage 22, expressed in somites and the pronephros. At stage 24 and 26, expressed in the pharyngeal arches I-III. At stage 31, expression in the eye, central nervous system and pharyngeal arches IV and V increases. Up to stage 34, expression becomes intense at the oral cavity and lateral line structures. At this stage, expression weakens in the pharyngeal arches, and increases in the epibranchial arches. Expressed in the digestive tract in stage 34 embryos. First expressed at a low level at stage 12, with expression gradually increasing up to stage 22. From stage 24, expression increases sharply and continues at a similar level as development progresses through the tadpole stages. Belongs to the TGF-beta family. GDNF subfamily.