Some properties of the specific androgen-binding activities in cultured human genital skin fibroblasts.

Specific 5 alpha-dihydrotestosterone (DHT)-binding activity in the cytosol (C) and 0.4 M KCl-extractable nuclear fraction (N) of cultured human fibroblast cell strains developed from preputial (n = 12) and labium majus (n = 12) skin were analyzed by gel exclusion chromatography, sucrose gradient sedimentation, and thermostability. Both fractions had activities that were excluded from Sephacryl S-200 columns; another component (mol wt, 20,000) was present in the N fraction. The C was more thermostable than a homologous N activity, and addition to the former of KCl to 0.4 M had no effect. There was large, overlapping variation in thermostability of the C and N activities among strains from either site, sister strains developed from a single skin biopsy, and even among serial subcultures within a strain; likewise, the variable sedimentability of the C (4-7S) and N (3.2-5.9S) activities prevented their consistent discrimination. Each type of variation occurred despite excellent intraexperimental replication. The thermostability of a given N activity varied directly with its sedimentation coefficient. By cluster analysis, the data relating thermostability of a given N activity with the percentage of 0.4 M KCl-resistant nuclear activity segregated into two populations; within each population these two measurements were related inversely. We suggest that these coordinate behaviors of the N activity reflect intrinsic properties of the androgen-receptor system in normal genital skin fibroblasts which may be useful for defining qualitative aberrations of the system in receptor-positive forms of congenital androgen insensitivity.     

Specific 5α-dihydrotestosterone binding in labial skin fibroblasts c1ultured from patients with male pseudohermaphroditism

The cytoplasm of skin fibroblasts serially subcultured from the labium majus of normal human females binds 5alpha-dihydrotestosterone (5alpha-DHT) with high affinity and low capacity. Such binding was absent from the strains of two male pseudohermaphrodites with unambiguous female external genitalia: one of these was from a patient with the clinical features and a family history typical of complete testicular feminization; the other merited the same diagnosis on anatomic and endocrine grounds, but had an XYY karyotype in multiple tissues, including the testes. Normal cytoplasmic binding was found in strains from two prepubertal male pseudohermaphrodites with bilateral inguinal testes: one had unambiguous female external genitalia, the other had clitoromegaly; the former had normal specific nuclear binding of 5alpha-DHT, and thereby the target cell capacity for pubertal masculinization. Measurement of specific 5alpha-DHT binding by cultured labial skin fibroblasts should be an early step in the investigation of male pseudohermaphroditism with female external genitalia.     

5alpha-reductase activity of genital and nongenital skin fibroblasts from patients with 5alpha-reductase deficiency, androgen insensitivity, or unknown forms of male pseudohermaphroditism

Serially subcultured fibroblast strains from genital (foreskin, labium majus) skin, as a group, have considerably more steroid (testosterone) 5alpha-reductase activity than those form nongenital skin. Foreskin strains varied 40-fold and labial strains even more. Labial strains overlapped nongenital strains of either sex more frequently than did prepuce strains. The activity of foreskin strains from two siblings with proven 5alpha-reductase deficiency was clearly lower than that of any of 18 control stains. The comparative behavior of the various strain types indicates that labial and nongenital strains should not be used to support a clinical suspicion of male pseudohermaphroditism due to 5alpha-reductase deficiency. The activities of labial strains from patients with complete androgen insensitivity (testicular feminization) - five with the receptor-negative variety and two with the receptor-positive type - were as variable as those of control labial strains. The decreased 5alpha-reductase activity observed in fresh skin slices of some patients is probably and expression of their functional estrogen/androgen imbalance in vivo.     

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

Maximum specific 5alpha-dihydrotestosterone (DHT) binding activity (Bmax) had been measured in intact confluent monolayers representing fibroblast strains derived form 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 Bmax 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 explant donors or with the in vitro age (mean population doubling level) of the cultures assayed. The Bmax activities of three nongenital strains from normal infants (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 Bmax values close to zero; the other two fell between 10 and 15 fmol/mg protein. It is apparant that labial skin fibroblast strains from clinically homogeneous patients with TF had highly variable degrees of DHT binding deficiency, and that they permit a more reliable diagnosis of severe and intermediate degrees of DHT binding deficiency than do strains of nongenital skin fibroblasts.     

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

pecific 5-dihydrotestosterone (DHT) binding capacity (B_max) has been determined for human skin fibroblast strains from nongenital 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 nongenital ones (32 vs. 11 fmollmg 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 ⁴ -3-ketosteroid 5-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.     

5α-Reductase activity of genital and nongenital skin fibroblasts from patients with 5α-reductase deficiency,androgen insensitivity,or unknown forms of male pseudohermaphroditism

Serially subcultured fibroblast strains from genital (foreskin, labium majus) skin, as a group, have considerably more steroid (testosterone) 5α-reductase activity than those from nongenital skin. Foreskin strains varied 40-fold and labial strains even more. Labial strains overlapped nongenital strains of either sex more frequently than did prepuce strains. The activity of foreskin strains from two siblings with proven 5α-reductase deficiency was clearly lower than that of any of 18 control strains. The comparative behavior of the various strain types indicates that labial and nongenital strains should not be used to support a clinical suspicion of male pseudohermaphroditism due to 5α-reductase deficiency. The activities of labial strains from patients with complete androgen insensitivity (testicular feminization) – five with the recptor-negative variety and two with the receptor-positive type – were as variable as those of control labial strains. The decreased 5α-reductase activity observed in fresh skin slices of some patients is probably an expression of their functional estrogen/ androgen imbalance in vivo.