Influence of prostaglandin F 2α and its analogues on hair regrowth and follicular melanogenesis in a murine model

Abstract

Abstract: Latanoprost and isopropyl unoprostone, which are analogues of prostaglandin F 2α (PGF 2α ), are promising drugs for the reduction of intra‐ocular pressure. However, they have been reported to have side effects, including hypertrichosis and hyperpigmentation of the eyelashes and periocular skin, and occasionally poliosis. In order to investigate these effects further, PGF 2α , latanoprost and isopropyl unoprostone were applied to the dorsal skin of 7‐week‐old C57BL/6 mice, and hair length was measured during the treatment. The three molecules all showed stimulatory effects on the murine hair follicles and the follicular melanocytes in both the telogen and anagen stages, and stimulated conversion from the telogen to the anagen phase. PGE 2 is known to act synergistically with PGF 2α , and hence the influence of PGE 2 was also examined. PGE 2 did not induce distinct telogen‐to‐anagen conversion, but showed moderate growth stimulatory effects on early anagen hair follicles. In addition, we observed a case of hypertrichosis and trichomegaly with an excess of melanogenesis, leading to the emergence of white hair, suggesting that poliosis can occur as a side effect of eye treatment with solutions of PGF 2α analogues. The stimulatory effects of PGF 2α and PGE 2 on hair growth have been discussed with regard to the role of protein kinase C and mast cells.