Figure 4. Topical forskolin promotes melanization of tyrosinase-intact K14-Scf mice irrespective of Mc1r status.

A) Wild type (Mc1r^E/E Tyr^wt/wt), heterozygote (Mc1r^E/e Tyr^wt/wt), extension (Mc1r^e/e Tyr^wt/wt), or albino extension (Mc1r^e/e Tyr^c2j/c2j) K14-Scf animals were depilated, and treated with vehicle (dotted lines) or forskolin (solid lines) as indicated once a day for five days each week (40 μmoles of forskolin per application) through 21 days. Skin color was recorded weekly and quantified on the black-white L* CIE color axis with darker skin having lower L* scores. B) Eumelanin and pheomelanin quantification of skin biopsies at the end of the experiment (day 21). * indicates statistical significance (p < 0.05) as compared to control-treated animals within the same strain.