Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.aquatox.2003.10.008
Title (Primary) Aromatase modulation alters gonadal differentiation in developing zebrafish (Danio rerio)
Author Fenske, M.; Segner, H.
Journal Aquatic Toxicology
Year 2004
Department OEC; COE
Volume 67
Issue 2
Page From 105
Page To 126
Language englisch
Keywords Fadrozole; Gene expression; 17α-Methyltestosterone (MT); P450 aromatase gene (CYP19); Zebrafish; Endocrine disruption; Feminisation; Masculinisation
Abstract This study investigated whether gonadal sex differentiation of zebrafish (Danio rerio) is susceptible to compounds that interfere with cytochrome P450 aromatase (P450arom). Treatment of zebrafish during the period of gonadal differentiation with either the non-steroidal aromatase inhibitor fadrozole or 17α-methyltestosterone (MT) changed gonad morphological differentiation and altered the pattern of P450arom gene (CYP19) expression. Application of fadrozole (500 μg/g of food) between days 35 and 71 post-fertilisation (pf) resulted in 100% masculinisation, i.e. the gonads of all individuals examined (n=40) showed testicular morphology. At the same time, fadrozole treatment suppressed gonadal CYP19A (gonad-derived CYP19 gene) mRNA expression, as assessed by means of semi-quantitative RT-PCR. After termination of fadrozole treatment at day 71 pf and subsequent rearing of zebrafish under control conditions until 161 days pf, the gonads of all individuals still displayed testicular morphology. Gonadal CYP19A expression, however, showed a dimorphic pattern, with 14 out of 22 individuals having low CYP19A mRNA levels similar to those found in testes of control fish, while eight fish showed high, ovary-like levels of gonadal CYP19A mRNA. MT treatment (10 μg/l) during the period of gonadal differentiation (days 35 to 71 pf) resulted in phenological feminisation, i.e., all fish examined (n=28) showed an ovarian gonadal morphology. While gonadal CYP19A expression was suppressed compared to control fish, cerebral CYP19B (brain-derived CYP19 gene) mRNA expression was increased in 71-day-old MT-treated fish. The results from this study provide evidence that exogenous compounds interfering with the P450arom system are able to disrupt, even persistently, gonadal sex differentiation of the protogynic zebrafish.
Persistent UFZ Identifier
Fenske, M., Segner, H. (2004):
Aromatase modulation alters gonadal differentiation in developing zebrafish (Danio rerio)
Aquat. Toxicol. 67 (2), 105 - 126