Epidermal Growth Factor Delays Development of Epidermis and Hair Follicles in Mice During First Coat Growth

The study investigated the effects of epidermal growth factor (EGF) on the development of the epidermis and hair follicles in male mice during the formation of their first coat. EGF treatment from birth resulted in a temporary thickening of the epidermis and maintained high levels of cell proliferation for 8 days, delaying the normal thinning process seen in control mice. This delay in epidermal development was accompanied by inhibited hair growth and reduced hair diameter, as EGF inhibited the growth of hair follicle bulbs and the increase in bulb cell numbers during the early anagen phase. Despite these changes, the size and cell numbers of the dermal papilla were not significantly affected. Overall, EGF delayed normal skin development by maintaining active proliferative and differentiation processes, leading to inhibited follicle development and hair growth.