Stimulation of aromatase activity by dihydrotestosterone in human skin fibroblasts.

In order to study the regulation of aromatase activity by androgens in cultured fibroblasts derived from genital skin of normal prepubertal boys, aromatase activity was evaluated in the presence of various concentrations of non-aromatizable androgen DHT(5 alpha-dihydrotestosterone). The estrogen formation was assayed by an enzymatic method, after 24 h incubation of the cells with 10(-6) M androstenedione. Aromatase activity was stimulated 3- to 20-fold by DHT at concentrations 10(-10) and 10(-9) M.

[Male pseudohermaphroditism caused by partial insensitivity to androgens. Clinical and biochemical heterogeneity].

Male pseudohermaphroditism due to partial androgen insensitivity (PAI) may be suspected clinically in case of incomplete masculinization of external genitalia in spite of age related plasma androgen levels. In 25 children or adolescents in whom PAI was suspected, the 5 alpha-reductase activity of external genitalia fibroblasts, the number of androgen receptor sites (Bmax) and the affinity of receptors for dihydrotestosterone (Kd) were studied. Clinical expression of PAI is highly polymorphic (Prader's type I to type IV), when most children (18/25) were considered as males.