DIFFERENCES IN TESTOSTERONE-METABOLISM BY BEARD AND SCALP HAIR FOLLICLE DERMAL PAPILLA CELLS

OBJECTIVE Androgens have paradoxically different effects on hair folli cles depending on body site, stimulating beard growth while inducing r egression in some areas of the scalp. The mesenchyme derived dermal pa pilla at the base of the hair follicle regulates many aspects of the g rowth of follicular epithelium, and is probably the site of androgen a ction. Since 5 alpha-dihydrotestosterone is considered to be the activ e intracellular androgen in many target tissues and is required for so me androgen-mediated hair growth, such androgen-sensitive cells should contain 5 alpha-reductase. This study was designed to investigate whe ther cultured human dermal papilla cells contain 5 alpha-reductase and whether the metabolic capacity varies with the body site of the folli cle in line with the clinical picture. DESIGN Testosterone metabolism in cultured dermal papilla cells from androgen sensitive beard follicl es was compared with less androgen dependent non-balding scalp follicl es. Primary cell cultures were established from follicles of 11 patien ts with normal hair growth. The cells were grown to confluence in lO-c m Petri dishes and incubated with 5 nM H-3-testosterone in serum-free medium for 2 hours. The cells and the culture medium were collected se parately for individual analysis. MEASUREMENTS Unlabelled carrier and C-14-marker steroids were added to both the cell and medium extracts b efore separation by thin-layer chromatography. The individual steroid identities were confirmed by recrystallizing up to five times to a con stant H-3/C-14 ratio. RESULTS Testosterone was taken up by both cell t ypes; significant amounts of 5 alpha-dihydrotestosterone were recovere d inside beard cells, but not in scalp cells, whereas androstenedione was identified in both. An unidentified compound was present intracell ularly in both cell types, but was not present in the culture medium. 5 alpha-Dihydrotestosterone was present only in the culture medium of beard cells but androstenedione was present in a similar amount in the medium from both cell types. The presence of other steroids could not be confirmed in either the cell extracts or the culture medium. CONCL USIONS The production of 5 alpha-dihydrotestosterone by beard cells co ncurs with the poor beard growth in men with 5 alpha-reductase deficie ncy, supporting our hypothesis that androgens mediate their effects on the hair follicle via the mesenchyme-derived dermal papilla.