title: Glucocorticoid stimulates melanogenesis and tyrosinase gene expression in B16 melanoma cells.
abstract: Effects of dexamethasone on melanogenesis and tyrosinase mRNA levels were determined in B16/F10 melanoma cells. Melanin content of B16 cells increased in a dose-dependent manner by the addition of dexamethasone to the culture medium. After 72 hr exposure, dexamethasone (10(-6) M) produced a 2.4-fold increase in melanin content. Northern blot analysis revealed that tyrosinase mRNA level also increased by the addition of dexamethasone to the culture medium. After 24 hr exposure, dexamethasone (10(-6) M) caused a 1.8-fold increase in tyrosinase mRNA levels. A tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA) decreased tyrosinase mRNA level at 30 nM concentration. Dexamethasone antagonized this TPA-mediated decrease in tyrosinase mRNA. It is suggested that glucocorticoids are involved in the regulation of tyrosinase activity at the transcriptional level.
authors.affiliation: Department of Dermatology, Kobe University School of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Ito
authors.forename: C
authors.initials: C
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Mishima
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D005938:Glucocorticoids / Q000502:physiology*; D008543:Melanins / Q000096:biosynthesis*; D008546:Melanoma, Experimental; D051379:Mice; D014442:Monophenol Monooxygenase / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D005938:Glucocorticoids; D008543:Melanins; D012333:RNA, Messenger; D003907:Dexamethasone; D014442:Monophenol Monooxygenase; D013755:Tetradecanoylphorbol Acetate