Abstract
The enzyme 5α-reductase converts testosterone to dihydrotestosterone and is required for male phenotypic sexual differentiation. There are two 5α-reductase genes in man that encode isozymes (designated types 1 and 2) with distinct biochemical and pharmacological properties and tissue distributions. Mutations in the gene encoding the type 2 isozyme cause male pseudohermaphroditism. The characterization of 27 mutations at the molecular and biochemical levels has revealed amino acids in the protein that participate in substrate and cofactor (NADPH) binding, as well as determinants of protein stability. An unexplained feature of this disease has been the occurrence of partial virilization at puberty in affected males. Determination of the developmental expression patterns of the two 5α-reductase isozymes by immunoblotting suggest that the observed virilization may be caused by expression of the type 1 isozyme in the liver and skin. This result suggests that dihydrotestosterone may act in a true endocrine fashion in addition to the autocrine and paracrine mechanisms typically ascribed to this androgen.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Russell, D. STEROID 5α-REDUCTASE TYPE 2 DEFICIENCY. Pediatr Res 33 (Suppl 5), S6 (1993). https://doi.org/10.1203/00006450-199305001-00025
Issue Date:
DOI: https://doi.org/10.1203/00006450-199305001-00025