Male pseudohermaphroditism presumably due to target organ unresponsiveness to androgens. Deficient 5alpha-dihydrotestosterone binding in cultured skin fibroblasts

one (DHT) binding activity (B.ax) has been measured in intact confluent monolayers representing fibroblast strains derived from nongenital and genital (labium majus) skin of normal individuals and of 11 patients fulfilling the clinicogenetic criteria of complete testicular feminization (TF). Nine labium majus strains from adult females had a mean Bmas value three times greater than that of seven nongenital strains from adult females (33 vs. 11 fmol/mg cell protein). The Bmax results for 13 adult nongenital strains varied from 5.6 to 23.3 fmol/ mg protein; the values for males and females had very similar means and ranges. The variation could not be correlated with the chronologic age of adult skin ex-plant donors or with the in vitro age (mean population doubling level) of the cultures assayed. The Bmax activities of three nongenital strains from normal in-fants (two male, one female) did not exceed 5 fmol/mg protein. Seven of eight nongenital TF strains had Bmax values below 2 fmol/mg protein; the value for the eighth coincided with the lower limit of normal adults. The lower limit of DHT binding in normal labium majus strains was 15 fmol/mg protein. Three of five labial strains from patients with TF had Bm.x values close to zero; the other two fell between 10 and 15 fmol/mg protein. It is apparent that labial skin fibro-blast strains from clinically homogeneous patients with Abstracts of portions of this work have appeared in Am