title: Utilization of exogenous tetrahydrobiopterin in nitric oxide synthesis in human neuroblastoma cell line.
abstract: We and others have previously reported that neurons expressing neuronal nitric oxide synthase (nNOS) do not co-express GTP cyclohydrolase I, the enzyme that synthesize its cofactor tetrahydrobiopterin (BH4). BH4 is released from catecholaminergic cells and nNOS-expressing cells are located close to BH4-producing catecholaminergic nerve terminals. We show that BH4 is taken up into the nNOS-expressing human neuroblastoma cells TGW-I-nu in a linear, dose-dependent manner and elevates NO production. Direct exposure to BH4, dihydrobiopterin or biopterin, or coculture with catecholaminergic CATH.a cells increases NO production by TGW-I-nu. Thus, BH4-requiring nNOS cells may obtain BH4 from neighboring catecholaminergic cells or terminals and an intercellular crosstalk may exist between the two cells in vivo.
authors: Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-ku, Seoul 138-736, South Korea.
authors: Hyun Jin
authors: HJ
authors: Choi
authors: Seong Who
authors: SW
authors: Kim
authors: Joo Hyuk
authors: JH
authors: Im
authors: Seong-Gene
authors: SG
authors: Lee
authors: MiJung
authors: M
authors: Kim
authors: Onyou
authors: O
authors: Hwang
mesh_terms: D001708:Biopterins / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis; D052248:Nitric Oxide Synthase Type I
chemical_list: D001708:Biopterins; D009569:Nitric Oxide; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C003402:sapropterin