Glial cell line-derived neurotrophic factor is expressed in penis of adult rat and retrogradely transported in penile parasympathetic and sensory nervesLaurikainen, A.; Hiltunen, J.O.; Vanhatalo, S.; Klinge, E.; Saarma, MartCell and tissue research2000 / p. 321-329 https://pubmed.ncbi.nlm.nih.gov/11151444/

Neurotrophin-3 is a target-derived neurotrophic factor for penile erection-inducing neuronsHiltunen, J.O.; Laurikainen, A.; Klinge, E.; Saarma, MartNeuroscience2005 / 1, p. 51-58 https://www.sciencedirect.com/science/article/pii/S0306452205000965

Neurturin is a neurotrophic factor for penile parasympathetic neurons in adult ratLaurikainen, A.; Hiltunen, J.O.; Thomas-Crusells, J.; Vanhatalo, S.; Arumäe, Urmas; Airaksinen, Matti S.; Klinge, E.; Saarma, MartJournal of neurobiology2000 / p. 198-205