UV Light May Induce Hypertrichosis Through Production of Prostaglandin E2

The document from 2007 suggests that UV light may induce hypertrichosis (excessive hair growth) by increasing the production of Prostaglandin E2 (PGE2) in the skin. UV irradiation activates cyclooxygenase-2 (COX-2) enzyme, leading to high levels of PGE2, which is known to stimulate hair growth. This is supported by observations that prostaglandins can stimulate eyelash, body, and scalp hair growth in various contexts, including the use of eye preparations for glaucoma and topical applications in animal models. The document also notes that PGE2 increases intracellular CAMP levels, which in turn stimulates Glucose-6-phosphate dehydrogenase (G6PD) activity, an enzyme whose activity increases during the anagen (growth) phase of the hair cycle. The inhibitory effects of dehydrotestosterone and dehydroepiandrosterone on hair growth are attributed to their inhibitory effects on adenyl cyclase and G6PD, respectively. Therefore, the document concludes that UV light may promote hypertrichosis through the production of PGE2.