Continuous PDGF-BB treatment of primary rat brain cell cultures resulted in outgrowth of neurites and prolonged survival.;The effects of i.c.v. infused platelet-derived growth factor and brain-derived neurotrophic factor on cell genesis, as assessed with bromodeoxyuridine (BrdU) incorporation, were studied in adult rats with unilateral 6-hydroxydopamine lesions. Both growth factors increased the numbers of newly formed cells in the striatum and substantia nigra to an equal extent following 10 days of treatment.;PDGF-BB but not PDGF-AA reduced the progressive loss of tyrosine hydroxylase- (TH)-positive neurons in rat and human cell cultures.