title: Androgens and male physiology the syndrome of 5alpha-reductase-2 deficiency.
abstract: Dihydrotestosterone (DHT), a potent androgen, is converted from testosterone by 5alpha-reductase isozymes. There are two 5alpha-reductase isozymes, type 1 and type 2 in humans and animals. These two isozymes have differential biochemical and molecular features. Mutations in type 2 isozyme cause male pseudohermaphroditism, and many mutations have been reported from various ethnic groups. The affected 46XY individuals have high normal to elevated plasma testosterone levels with decreased DHT levels and elevated testosterone/DHT ratios. They have ambiguous external genitalia at birth so that they are believed to be girls and are often raised as such. However, Wolffian differentiation occurs normally and they have epididymides, vas deferens and seminal vesicles. Virilization occurs at puberty frequently with a gender role change. The prostate in adulthood is small and rudimentary, and facial and body hair is absent or decreased. Balding has not been reported. Spermatogenesis is normal if the testes are descended. The clinical, biochemical and molecular genetic analyses of 5alpha-reductase-2 deficiency highlight the significance of DHT in male sexual differentiation and male pathophysiology.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolisms, Department of Medicine, Weill Medical College, Cornell University, 1300 York Avenue, Box 149, Room F-260, New York, NY 10021, USA. jimperat@mail.med.cornell.edu
authors.forename: J
authors.initials: J
authors.lastname: Imperato-McGinley
authors.forename: Y-S
authors.initials: YS
authors.lastname: Zhu
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000172:deficiency* / Q000235:genetics / Q000502:physiology*; D000728:Androgens / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D012734:Disorders of Sex Development / Q000201:enzymology*; D005260:Female; D005783:Gender Identity; D005835:Genitalia / Q000002:abnormalities; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008297:Male; D011467:Prostate / Q000473:pathology; D012733:Sex Differentiation / Q000502:physiology; D013577:Syndrome
chemical_list: D000728:Androgens; D007527:Isoenzymes; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase