Melanogenesis in cultured melanocytes can be substantially influenced by L-tyrosine and L-cysteine.
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.
Smit
N P
NP
Department of Dermatology, Leiden University Hospital, The Netherlands.
Van der Meulen
H
H
Koerten
H K
HK
Kolb
R M
RM
Mommaas
A M
AM
Lentjes
E G
EG
Pavel
S
S
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*
D003470:Culture Media; D008543:Melanins; D014443:Tyrosine; D003545:Cysteine