Effect of L - tyrosine on Proliferation and Melanization in Cultured Normal Human Melanocytes.
- Author:
Mu Hyoung LEE
1
;
Jin Hwan KIM
;
Jai Kyung PARK
;
Choong Rim HAW
Author Information
1. Department of Dermatology, Immunology Research Laboratory, Korea.
- Publication Type:Original Article
- Keywords:
L-tyrosine;
Melanization;
Normal human melanocyte;
Proliferation
- MeSH:
Dihydroxyphenylalanine;
Humans*;
Levodopa;
Melanins;
Melanocytes*;
Melanoma;
Monophenol Monooxygenase;
Tics;
Tyrosine*
- From:Korean Journal of Dermatology
1996;34(1):25-30
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: The biosynthesis of melanin is initiated by the enzymatic oxidation of L-tyrosine to L-dopa by tyrosinase. Some precursors of melanin are cytotoxic, and melanoma cells are killed as a risk of exposare to excess tyrosine or dopa in the culture medium. However, there have been few observations of the effects of L-tyrosine on cultured normal human melanocyte. OBJECTIVE: In order to investigate whether exogenous tyrosine induces cytotoxicity in cultured normal human melanocytes as in melanoma cells, we examined the effects of L-tyrosine on proliferation and melanization in normal human melanocytes. METHODS: A melanocyte culture was produced with a modified TIC medium. L-tyrosine was added to the culture medium, 100, 200, 400, and 800uM. After 2 days of incubation, the proliferation was measured by methylthiazol tetrazolium(MTT) assay and sulforhodamine B(SRB) assay. The melanin contenis were also measured by the modified Whittaker's method. RESULTS: On MTT assay, the proliferation of melanocytes had been stirnulated significantly (p< 0.05) in all L-tyrosine added groups. On SRB assay, the proliferation of melanocytes had heen stimulated significantly (p<005) in 200, 400, 800uM of L-tyrosine added groups. The melanin contents had increased in all L-tyrosine added groups, and had increased significantly (p<0.05) in 400uM of L-tyrosine added group. CONCLUSION: L-tyrosine is not toxic to normal melanocytes, It stimulates the proliferation and melnization of cultured normal human melanocytes.
