Stimulation of tyrosinase by dihydroxy phenyl derivatives.

Isoprenaline (0.3 mM) moderately increased the tyrosinase activity of cultured human melanoma cells, while another beta-adrenoceptor agonist, terbutaline (1-3 mM) and a catechol compound, dopac (0.1-0.3 mM) induced a several fold increase in the enzyme activity. Isoprenaline (0.3-1 mM) and dopac (0.3-1 mM) also exerted pronounced toxic effects on the cells. The data suggest: 1) a possible role for beta-adrenoceptors in the regulation of human melanogenesis; 2) two different ways of action for isoprenaline in inducing tyrosinase elevation; 3) the possible usefulness of dopac as a chemotherapeutic agent.