Expression of androgen-responsive properties in human skin fibroblast strains of genital and nongenital origin

Specific 5alpha-dihydrotestosterone (DHT) binding capacity (Bmax) has been determined for human skin fibroblast strains from non-genital areas of males and females (N = 8), as well as prepuce and labium majus (N = 9). Genital strains had a mean three times that of non-genital ones (32 vs. 11 fmol/mg cell protein). There were no sex differences. Variation among strains was not simply correlated with donor age; that within strains was unrelated to in vitro age. The lowest values for genital strains overlapped the nongenital ones; those of the nongenital strains approached the limit of detectability. These results parallel those for delta4-3-ketosteroid 5alpha-reductase activity. Thus, serially cultured genital and nongenital skin fibroblasts express their relative differentiative ancestry as androgen target cells. This expression may affect the diagnosis of androgen insensitivity and certain inborn errors of metabolism; its variability is discussed in terms of clonal heterogeneity.