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 mitotic and labeling indices in basal cells for 8 days, delaying the normal thinning process seen in controls. Hair growth rate and hair diameter were inhibited in EGF-treated mice, with changes observed in the follicle bulb, although the dermal papilla size and cell numbers remained unchanged. The findings suggested that EGF delayed normal skin development by keeping proliferative and differentiation processes active, thereby inhibiting follicle development and hair growth.