title: An aromatase inhibitor or high water temperature induce oocyte apoptosis and depletion of P450 aromatase activity in the gonads of genetic female zebrafish during sex-reversal.
abstract: Dietary administration of a cytochrome P450 aromatase (P450arom) inhibitor (fadrozole) in genetic female juveniles of zebrafish (Danio rerio) was performed at 15-40 days post-hatching. The percentage of gonadal masculinization in the genetic all-females at 40 days post-hatching, treated with 0, 10, 100 and 1000 microg fadrozole g(-1) diet(-1) were 0, 62.5, 100 and 100%, respectively. Rearing at high water temperature in genetic all-females was performed at 15-25 days post-hatching. The percentage of gonadal masculinization in the genetic all-females at 40 days post-hatching, at water temperatures of 28.5, 35 and 37 degrees C were 0, 68.8 and 100%, respectively. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive oocytes of early diplotene and perinucleolar stages in fadrozole-treated genetic females (1000 microg g(-1) diet(-1)) were observed at 15-40 days post-hatching during sex-reversal. In contrast, apoptotic oocytes of early diplotene stage in high temperature-treated genetic females (at 35 and 37 degrees C) during sex-reversal and presumptive males of wild-type fish during sex differentiation were found at 15-27 days post-hatching. Our findings indicate that oocyte apoptosis, depletion of P450arom activity and differentiation of spermatogonia during gonadal sex-reversal are caused by treatments of aromatase inhibitor or high water temperature.
authors.affiliation: Graduate School of Integrated Science, Yokohama City University, Seto, Kanazawa-ku, 236-0027, Yokohama, Japan. udaisuke@yokohama-cu.ac.jp
authors.forename: Daisuke
authors.initials: D
authors.lastname: Uchida
authors.forename: Michiaki
authors.initials: M
authors.lastname: Yamashita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kitano
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001141:Aromatase / Q000378:metabolism*; D047072:Aromatase Inhibitors; D004032:Diet; D012734:Disorders of Sex Development; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D017316:Fadrozole / Q000494:pharmacology; D005260:Female; D006066:Gonads / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D006358:Hot Temperature; D008297:Male; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D012727:Sex Characteristics; D013997:Time Factors; D014867:Water / Q000494:pharmacology; D015027:Zebrafish
chemical_list: D047072:Aromatase Inhibitors; D004791:Enzyme Inhibitors; D014867:Water; D001141:Aromatase; D017316:Fadrozole