抄録
It is well-known that the oxidative stress activates melanogenesis which relates with DNA damage. On the other hand, it was reported that tyrosinase, the enzyme that controls the synthesis of melanin, was regulated by the extra-cellular glucose level. First we culture B16 cells in high/low glucose conditions and confirmed that the melanogenesis was suppressed in low-glucose conditions. Then we compare this little-known melanogenesis induced by low-glucose conditions and that by the oxidative stress. Peroxide, typical oxidizing agent, increased melanosome production, and broke mtDNA detected with LA-PCR. On the other hand, B16 cells cultured in the low-glucose medium showed the melanogenesis without mtDNA fragmentation. Expression of tyrosinase, TRP1 and TRP2 were measured by real-time RT-PCR. Since glucose enters into cells across glucose transporters (GLUTs), we analyzed the expression of them. Anti-oxidants can suppress melanogenesis caused by peroxide, on the other hand some anti-oxidants failed to suppress the melanogenesis in low glucose conditions. From these results, we suggest that melanogenesis in low glucose conditions was enhanced by the different mechanism from that by oxidative stress. [J Physiol Sci. 2007;57 Suppl:S129]
