In vitro effects of testosterone, dihydrotestosterone and estradiol on cell growth of human hair bulb papilla cells and hair root sheath fibroblasts.

The influence of testosterone, dihydrotestosterone (each 10 ng/ml up to 300 ng/ml) and estradiol (0.2 ng/ml up to 10 ng/ml) on the growth behaviour (cell count, [3H]thymidine uptake, cell doubling time) of subcultured human hair bulb papilla cells and hair root sheath fibroblasts was studied. Papilla cells and root sheath fibroblasts were isolated by microdissection from the same anagen hair follicles obtained from biopsies of androgen-sensitive scalp regions in 6 healthy male subjects. Dihydrotestosterone and testosterone concentrations above 30 ng/ml significantly reduced the growth of both cell types; lower doses had no effect. Estradiol had no distinct influence on the growth curves of either cell type up to 10 ng/ml, whereas higher concentrations significantly increased the growth of both cell types as shown by [3H]thymidine uptake. Papilla cells reacted more sensitively than root sheath fibroblast to dihydrotestosterone and testosterone, as shown by the growth curves, [3H]thymidine uptake, and cell doubling time.