title: Stimulation of the proliferation and differentiation of mouse pink-eyed dilution epidermal melanocytes by excess tyrosine in serum-free primary culture.
abstract: The epidermal cell suspensions of the neonatal dorsal skin derived from wild type mouse at the pink-eyed dilution (p) locus (black, C57BL/10JHir-P/P) and their congenic mutant mouse (pink-eyed dilution, C57BL/10JHir-p/p) were cultured with a serum-free melanocyte growth medium supplemented with additional L-tyrosine (Tyr) from initiation of the primary culture. L-Tyr inhibited the proliferation of P/Pmelanocytes in a dose-dependent manner, whereas L-Tyr stimulated the proliferation of p/p melanoblasts and melanocytes regardless of dose. On the other hand, L-Tyr stimulated (P/P) or induced (p/p) the differentiation of epidermal melanocytes in a dose-dependent manner. In both P/P and p/p melanoblasts and melanocytes cultured with 2.0 mM L-Tyr for 14 days, slight increases in contents of eumelanin marker, pyrrole-2,3,5-tricarboxylic acid (PTCA) and pheomelanin marker, aminohydroxyphenylalanine (AHP) were observed. The average number of total melanosomes (stages I, II, III, and IV) per P/P melanocyte was not changed by L-Tyr treatment, but the proportion of stage IV melanosomes in the total melanosomes was increased. On the contrary, in p/p melanoblasts and melanocytes L-Tyr increased dramatically the number of stage II, III, and IV melanosomes as well as the proportion of stage III melanosomes. Contents of PTCA and eumelanin precursor, 5,6-dihydroxyindole-2-carboxylic acid (DHICA) of cultured media in p/p melanocytes were much more greatly increased than in P/P melanocytes. However, contents of AHP and pheomelanin precursor, 5-S-cysteinyldopa (5-S-CD) of cultured media in p/p melanocytes were increased in a similar tendency to P/Pmelanocytes. These results suggest that p/p melanocytes in the primary culture are induced to synthesize eumelanin by excess L-Tyr, but difficult to accumulate them in melanosomes.
authors.affiliation: Radiation Hazards Research Group, National Institute of Radiological Sciences, Anagawa, Chiba, Japan. thirobe@nirs.go.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hirobe
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Wakamatsu
authors.forename: Shosuke
authors.initials: S
authors.lastname: Ito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kawa
authors.forename: Masako
authors.initials: M
authors.lastname: Mizoguchi
mesh_terms: D000818:Animals; D002352:Carrier Proteins; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D007211:Indoles / Q000378:metabolism; D008297:Male; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010088:Oxidoreductases; D011506:Proteins / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism; D014443:Tyrosine / Q000187:drug effects / Q000378:metabolism*
chemical_list: C092922:5-S-cysteinyl-3,4-dihydroxyphenylalanine; D002352:Carrier Proteins; D016895:Culture Media, Serum-Free; D007211:Indoles; D008543:Melanins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011506:Proteins; D011758:Pyrroles; C018362:pheomelanin; C076239:P protein, mouse; D014443:Tyrosine; C030692:5,6-dihydroxy-2-indolylcarboxylic acid; D004295:Dihydroxyphenylalanine; C071226:pyrrole-2,3,5-tricarboxylic acid; D010088:Oxidoreductases; C079621:Tyrp1 protein, mouse; C064056:tyrosinase-related protein-1; D014442:Monophenol Monooxygenase; D019009:Proto-Oncogene Proteins c-kit