title: Melanogenesis in cultured melanocytes can be substantially influenced by L-tyrosine and L-cysteine.
abstract: We investigated the effect of varying concentration of 1-tyrosine and 1-cysteine in culture medium on melanin production by human skin melanocytes (skin phototype II/III). In addition to the analyses of dopa oxidase activity and total melanin, pheomelanin production in the cells was assessed by high-performance liquid chromatography determinations of pheomelanin degradation products, 3-aminotyrosine and 4-amino-3-hydroxyphenylalanine. As another marker for pheomelanin, melanosomal sulfur was determined by the use of X-ray microanalysis. With varying concentration of both amino acids, profound changes in the pigmentation patterns of the melanocytes were observed. A high concentration of 1-tyrosine (0.2 mM) was always connected with increased pigmentation. In combination with a low 1-cysteine content we saw an increase in tyrosinase activity and the highest melanin content. At high concentrations of both 1-tyrosine and 1-cysteine, the melanocytes showed reduced tyrosinase activity and they produced notably more pheomelanin. In case of the pheomelanin measurements by high-performance liquid chromatography and the sulfur detection with X-ray microanalysis, strongly increased concentrations were found when cells were maintained in high 1-tyrosine medium as compared with those grown with low 1-tyrosine. This was especially true for the combination with low 1-cysteine showing that the 1-tyrosine content of the medium strongly influences not only the eumelanin but also the pheomelanin production in the cultured melanocyte. It can be concluded that variations in the concentrations of 1-tyrosine and 1-cysteine in culture medium can be used to regulate the melanogenetic phenotype under in vitro conditions.
authors.affiliation: Department of Dermatology, Leiden University Hospital, The Netherlands.
authors.forename: N P
authors.initials: NP
authors.lastname: Smit
authors.forename: H
authors.initials: H
authors.lastname: Van der Meulen
authors.forename: H K
authors.initials: HK
authors.lastname: Koerten
authors.forename: R M
authors.initials: RM
authors.lastname: Kolb
authors.forename: A M
authors.initials: AM
authors.lastname: Mommaas
authors.forename: E G
authors.initials: EG
authors.lastname: Lentjes
authors.forename: S
authors.initials: S
authors.lastname: Pavel
mesh_terms: D002478:Cells, Cultured; D003470:Culture Media; D003545:Cysteine / Q000494:pharmacology*; D006801:Humans; D008543:Melanins / Q000096:biosynthesis*; D008544:Melanocytes / Q000378:metabolism*; D010858:Pigmentation; D014443:Tyrosine / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D008543:Melanins; D014443:Tyrosine; D003545:Cysteine