Generalized cutaneous hyperpigmentation in hairless mice induced by topical dimethylbenzanthracene.

The skin of hairless (Ng/Bln) mice topically treated with dimethylbenzanthracene (DMBA) was investigated by light microscopy, histochemistry, electron microscopy and autoradiography in order to gain some insight into the mechanisms by which the DMBA-induced cutaneous hyperpigmentation is mediated. The results of the present study indicate that this phenomenon is due to the DMBA-induced stimulation of both the tyrosinase system and the mitotic activity of dopa-inactive dormant melanocytes.