Epidermal growth factor, but not cortisol, suppresses fibre growth in cultured follicles

This experiment was conducted to examine the role of cortisol and epidermal growth factor (EGF) in the growth of cultured follicles. Intact Tukidale and Romney anagen hair follicles (n=12/dose) were isolated from skin strips and maintained in Williams E medium supplemented with 1 mM L-glutamine, Fungizone and antibiotics. Measurement of the changes in length of the follicles was made using an image analysis system. Tukidale and Romney follicles were incubated in medium containing 0, 10, 50 and 1000 ng/ml of cortisol for a period of 3 days. The average growth rate of Tukidale primary and secondary and Romney follicles was 406 (range 146–764), 173 (108–307) and 255 (81–546) μm/day respectively. The pattern of [methyl-3H] thymidine uptake showed that a typical pattern of DNA synthesis is taking place in culture follicles. Physiological and supra-physiological concentrations of 0, 10, 50 and 1000 ng/ml of cortisol had no effect on the growth of Tukidale primary and secondary follicles over a 3 days period. Similarly at the same concentrations, cortisol had no effect on fibre growth from Romney follicles. Tukidale primary follicles with dermis and without dermis maintained with cortisol at 0 and 50 ng/ml (n=12/dose/treatment) over a period of 6 days had no effect on follicle growth. EGF concentrations at 0.25, 0.5, 1, 25 and 50 ng/ml significantly (P