title: Induction of female-to-male sex change in adult zebrafish by aromatase inhibitor treatment.
abstract: This study investigated whether undifferentiated germ and/or somatic stem cells remain in the differentiated ovary of a species that does not undergo sex changes under natural conditions and retain their sexual plasticity. The effect of aromatase inhibitor (AI)-treatment on sexually mature female zebrafish was examined. A 5-month AI treatment caused retraction of the ovaries after which testes-like organs appeared, and cyst structures filled with spermatozoa-like cells were observed in sections of these tissues. Electron microscopic observations revealed that these cells appeared as large sperm heads without tails. Sperm formation was re-examined after changing the diet to an AI-free food. A large number of normal sperm were obtained after eight weeks, and no formation of ovarian tissue was observed. Artificial fertilization using sperm from the sex-changed females was successful. These results demonstrated that sex plasticity remains in the mature ovaries of this species.
authors.affiliation: Department of Biology, Faculty of Science, National University Corporation Shizuoka University, Oya 836, Suruga-ku, Shizuoka 422-8529, Japan.
authors.forename: Kanae
authors.initials: K
authors.lastname: Takatsu
authors.forename: Kaori
authors.initials: K
authors.lastname: Miyaoku
authors.forename: Shimi Rani
authors.initials: SR
authors.lastname: Roy
authors.forename: Yuki
authors.initials: Y
authors.lastname: Murono
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sago
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Itagaki
authors.forename: Masaru
authors.initials: M
authors.lastname: Nakamura
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Tokumoto
mesh_terms: D000818:Animals; D047072:Aromatase Inhibitors / Q000494:pharmacology*; D005260:Female; D008297:Male; D010053:Ovary / Q000187:drug effects; D019849:Sex Determination Processes / Q000187:drug effects*; D012733:Sex Differentiation / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects; D013737:Testis / Q000187:drug effects; D015027:Zebrafish / Q000254:growth & development*
chemical_list: D047072:Aromatase Inhibitors