Sex steroids in the female zebrafish (Danio rerio). Effects of cyproterone acetate and leachate-contaminated sediment extract.
In Molnbyggen, a leachate-contaminated lake in Sweden, effects on the reproductive system of perch included a decreased frequency of sexually mature female perch, reduced gonadosomatic index and decreased plasma levels of androstenedione and testosterone, but the contaminants responsible for these effects have not yet been identified. A biomarker-directed fractionation approach could be used to narrow the search for the compound(s) responsible for the adverse effects in Molnbyggen female perch. Thus, it is important to develop and test a suitable biomarker, which can be used in this type of approach. We evaluated if decreased concentrations of sex steroids could work as an in vivo end-point in female zebrafish fed an organic extract of bottom sediments from Molnbyggen. The responsiveness of zebrafish to endocrine alteration was evaluated using a positive control substance, cyproterone acetate (CA), which is known to inhibit steroid biosynthesis. After the 21-day exposure period the concentrations of testosterone (T) and estradiol (E2) were successfully determined by HRGC/HRMS in whole-body homogenates of individual fish. Median T concentrations were 1.7pmol/g fish in controls and were decreased after exposure both to CA (0.55pmol/g fish) and Molnbyggen sediment extract (1.2-1.3pmol/g fish). Median E2 concentrations were 5.3pmol/g fish in controls and were decreased after CA exposure (2.3pmol/g fish) and after exposure to Molnbyggen sediment extract (4.0-4.5pmol/g fish). This suggests that sex steroid concentrations in zebrafish are responsive to endocrine alteration and indicates that compounds with endocrine altering potency are present in Molnbyggen sediments.
Linderoth
Maria
M
Department of Applied Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden. maria.linderoth@itm.su.se
Ledesma
Mariana
M
Zebühr
Yngve
Y
Balk
Lennart
L
D000726:Androgen Antagonists / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D017373:Cyproterone Acetate / Q000008:administration & dosage / Q000633:toxicity*; D004703:Endocrine System / Q000187:drug effects*; D004781:Environmental Exposure; D005260:Female; D019015:Geologic Sediments / Q000737:chemistry*; D012739:Gonadal Steroid Hormones / Q000032:analysis; D008297:Male; D012098:Reproduction / Q000187:drug effects; D013548:Sweden; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000502:physiology*
D000726:Androgen Antagonists; D012739:Gonadal Steroid Hormones; D014874:Water Pollutants, Chemical; D017373:Cyproterone Acetate