Specific 5alpha-dihydrotestosterone binding in labial skin fibroblasts cultured 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.