Regulation of Melanogenesis as Studied by Chemical Analysis of Melanins

  • Ito, Shosuke (Fujita Health University School of Health Sciences)
  • Published : 2000.06.01

Abstract

- Biochemical studies show that in the process of mixed melanogenesis, cysteinyldopas are produced first which are next oxidized to give pheomelanin. After all of the cysteine is consumed, eumelanin is then deposited on the preformed pheomelanin. - In vitro and in vivo studies show that tyrosinase activity is the most important factor that regulates the switch of melanogenesis, with higher activities increasing melanogenesis, especially eumelanogenesis. - In culturted melanocytes, the tyrosine to cysteine ratio is critical in determining the eumelanin to pheomelanin ratio. - Our HPLC method to analyze eumelanin and pheomelanin has become a useful tool in the study of melanogenesis regulation. There are many problems to be solved before we fully understand the regulation of melanogenesis. Mutations in mouse models are ideal models for studying the genetic and molecular control of melanogenesis. Even in the mouse models, it is not known how cysteine is excluded from being incorporated into melanins in black and other eumelaninc mice, Conversely, it is not known how cysteine is continuously incorporated into pheomelanin in lethal yellow and recessive yellow mice.

Keywords

References

  1. The Pigmentary System: Pathology and Pathophysiololgy Advances in chemical analysis of melanins. In: Nordlund JJ, Biossy RE, Hearing VJ, King RA, Ortnonne JP Ito S.
  2. Pigment Cell Res Chemical analysis of of melanins and its application to the study of the regulation of melangenesis Ito S.;Wakamatsu K;Ozeki. H.
  3. Anal Biochem v.144 Microanlysis of eumelanin and pheomelanin in hair and melanomas by chemical degradation and liquid chromatography Ito S;Fujita K.
  4. Pigment Cell Res v.9 Spectrophotometric characterization of eumelanin and pheomelanin in hair Ozeki H.:Ito S.; Wakamatsu K.; Thody AJ.
  5. Biochim Biophys Acta v.1336 Chemical characterization of pheomelanogenesis starting from dihydroxyphenylalanine and cysteine. Effects of tyrosinase and cysteine concentrations and reaction time Ozeki H.;Ito S.;Wakamatsu K.;Ishiguro I.
  6. The Coat Colors of Mice: A Model for Mammalian Gene Action and Interaction Silver WK.
  7. Annu Rev Genet v.28 Molecular and developmental genetics of mouse coat color Jackson IJ.
  8. J Endocrinol v.109 Melanocyte-stimulating hormone, tyrosinase activity and th regulation of eumelanogenesis and phaeomelanogenesis in the hair follicular melanocytes of the mouse Burchill SA.;Thody AJ;Ito S.
  9. J Invest Dermatol v.97 Phaeomelanin as well as eumelanin is present in human epidermis Thody AJ;Higgins EM;Wakamatsu K;Ito S;Burchill SA;Marks JM