An aromatase inhibitor and tamoxifen decrease plasma levels of o,p'-DDT and its metabolites in Nile tilapia
Olga Leaños-Castañeda1, Gerardo Gold-Bouchot, Glen Van Der Kraak
1Departamento de Recursos del Mar, CINVESTAV Unidad Mérida, Carretera Antigua a Progreso km. 6, Ap. Postal 73 "Cordemex", Mérida, Yucatán 97310, México.
Abstract:
The objective of this study was to determine if tamoxifen or an aromatase inhibitor (4-hydroxyandrostenedione; 4-OHA) affected plasma concentrations of o,p' -DDT and its metabolites, o,p'-DDD and o,p'-DDE, in mature tilapia. Male and female tilapia were injected 6 times intraperitoneally with o,p'-DDT (40 mg/kg) alone or in combination with 4-OHA (2 mg/kg) over a 12 day period. An additional group of male fish was injected with tamoxifen (5 mg/kg) plus o,p'-DDT. At the end of the treatment period, plasma samples were extracted and analyzed by GC/ECD. Females injected only with o,p'-DDT had significantly higher levels of o,p'-DDT compared with males. Interestingly, females and males treated concomitantly with o,p'-DDT and 4-OHA or tamoxifen had significantly lower concentrations of plasma o,p'-DDT (about 50%) compared with fish treated with only o,p'-DDT. These initial results suggest that an interaction between endocrine-active compounds occurs in vivo in tilapia and may involve alterations in metabolism of o,p'-DDT.
Insights
Tamoxifen and 4-hydroxyandrostenedione (4-OHA) significantly reduced plasma concentrations of the environmental contaminant o,p
Area of Science:
- Environmental Toxicology
- Endocrinology
- Fish Biology
Background:
- Persistent organic pollutants like o,p' -DDT can disrupt endocrine systems.
- Tilapia are a model organism for studying the effects of environmental contaminants.
Purpose of the Study:
- To investigate the impact of tamoxifen and 4-hydroxyandrostenedione (4-OHA) on o,p' -DDT plasma levels in tilapia.
- To explore potential interactions between endocrine-active compounds and DDT metabolism in vivo.
Main Methods:
- Mature male and female tilapia were administered o,p' -DDT alone or with 4-OHA or tamoxifen via intraperitoneal injection over 12 days.
- Plasma samples were analyzed using Gas Chromatography with Electron Capture Detection (GC/ECD).
Main Results:
- Females exhibited higher o,p' -DDT plasma levels than males when treated solely with o,p' -DDT.
- Co-administration of 4-OHA or tamoxifen with o,p' -DDT led to a significant reduction (approximately 50%) in plasma o,p' -DDT concentrations in both sexes.
- These findings suggest an in vivo interaction between endocrine-active compounds and o,p' -DDT metabolism.
Conclusions:
- Tamoxifen and 4-OHA influence the pharmacokinetics of o,p' -DDT in tilapia.
- Endocrine disruption may involve altered metabolism of environmental contaminants.
- Further research is warranted to elucidate the specific mechanisms of interaction.
