Epidermal Growth Factor, But Not Cortisol, Suppresses Fiber Growth in Cultured Follicles

The study investigated the effects of cortisol and epidermal growth factor (EGF) on the growth of cultured hair follicles from Tukidale and Romney sheep. It was found that cortisol, at various concentrations, did not affect the growth of these follicles over a 3-day period. In contrast, EGF significantly reduced fibre growth at concentrations ranging from 0.25 to 50 ng/ml, causing noticeable morphological changes in the follicle bulb. This suggested that while cortisol did not influence fibre growth in this setting, EGF played a role in suppressing it, potentially contributing to wool breaks.