Influence of prostaglandin F_2α and its analogues on hair regrowth and follicular melanogenesis in a murine model

In a study from 2005, prostaglandin F2alpha (PGF2alpha) and its analogues, latanoprost and isopropyl unoprostone, were found to stimulate hair growth and follicular melanogenesis in 7-week-old C57BL/6 mice. These compounds were applied to the mice's dorsal skin, and they promoted hair growth in both the resting (telogen) and growth (anagen) phases of the hair cycle, as well as induced the transition from telogen to anagen phase. Prostaglandin E2 (PGE2), which acts synergistically with PGF2alpha, did not trigger a distinct transition from telogen to anagen but did moderately stimulate hair growth in early anagen follicles. The study also noted a case of hypertrichosis (excessive hair growth) and trichomegaly (abnormally long eyelashes) accompanied by an increase in melanogenesis, which led to the appearance of white hair, indicating that poliosis (whitening of the hair) could be a side effect of PGF2alpha analogues used in eye treatments. The role of protein kinase C and mast cells in the stimulatory effects of PGF2alpha and PGE2 on hair growth was discussed.