title: On the role of melatonin in skin physiology and pathology.
abstract: Melatonin has been experimentally implicated in skin functions such as hair growth cycling, fur pigmentation, and melanoma control, and melatonin receptors are expressed in several skin cells including normal and malignant keratinocytes, melanocytes, and fibroblasts. Melatonin is also able to suppress ultraviolet (UV)-induced damage to skin cells and shows strong antioxidant activity in UV exposed cells. Moreover, we recently uncovered expression in the skin of the biochemical machinery involved in the sequential transformation of l-tryptophan to serotonin and melatonin. Existence of the biosynthetic pathway was confirmed by detection of the corresponding genes and proteins with actual demonstration of enzymatic activities for tryptophan hydroxylase, serotonin N-acetyl-transferase, and hydroxyindole-O-methyltransferase in extracts from skin and skin cells. Initial evidence for in vivo synthesis of melatonin and its metabolism was obtained in hamster skin organ culture and in one melanoma line. Therefore, we propose that melatonin (synthesized locally or delivered topically) could counteract or buffer external (environmental) or internal stresses to preserve the biological integrity of the organ and to maintain its home-ostasis. Furthermore, melatonin could have a role in protection against solar radiation or even in the management of skin diseases.
authors.affiliation: Department of Pathology and Laboratory Medicine, Health Science Center, University of Tennessee, Memphis, TN 38103, USA. aslominski@utmem.edu
authors.forename: Andrzej
authors.initials: A
authors.lastname: Slominski
authors.forename: Tobias W
authors.initials: TW
authors.lastname: Fischer
authors.forename: Michal A
authors.initials: MA
authors.lastname: Zmijewski
authors.forename: Jacobo
authors.initials: J
authors.lastname: Wortsman
authors.forename: Igor
authors.initials: I
authors.lastname: Semak
authors.forename: Blazej
authors.initials: B
authors.lastname: Zbytek
authors.forename: Radomir M
authors.initials: RM
authors.lastname: Slominski
authors.forename: Desmond J
authors.initials: DJ
authors.lastname: Tobin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008550:Melatonin / Q000096:biosynthesis / Q000502:physiology*; D008969:Molecular Sequence Data; D010641:Phenotype; D044094:Receptors, Melatonin / Q000378:metabolism; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D012871:Skin Diseases / Q000378:metabolism / Q000473:pathology*; D012878:Skin Neoplasms / Q000378:metabolism; D012879:Skin Physiological Phenomena / Q000187:drug effects*
chemical_list: D044094:Receptors, Melatonin; D008550:Melatonin