Pyrroloquinoline quinone (PQQ) inhibits the expression of tyrosinase mRNA by alpha-melanocyte stimulating hormone in murine B16 melanoma cells.

The biological functions of pyrroloquinoline quinone (PQQ), a bacterial redox coenzyme and potent radical scavenger, have not been elucidated in mammals. In this paper, we studied the effects of PQQ on tyrosinase activity and subsequent melanogenesis in murine B16-F10 melanoma and found that alpha-Melanocyte stimulating hormone (MSH)-induced melanogenesis was inhibited by 6.3 to 25 microM PQQ in a dose-dependent manner. Moreover, PQQ inhibited MSH-induced tyrosinase activity by suppressing tyrosinase mRNA expressed by MSH. However, PQQ had no effect on MSH-stimulated cyclic adenosine 3', 5'-monophosphate (cAMP) production. These observations suggest that PQQ inhibits the expression of tyrosinase mRNA at a post receptor level and that PQQ may be useful in investigating hormone actions mediated by cAMP.