Fluoxetine, a selective serotonin re-uptake inhibitor (SSRI) and the active ingredient in Prozac®, is found in the environment and disrupts feeding and metabolism in exposed fish. The objective of this research was to investigate the mechanisms involved in the feeding and metabolism disruption in the model goldfish (Carassius auratus). Two short-term waterborne fluoxetine exposures (7- and 14-days) were performed using two environmentally relevant doses of fluoxetine (0.5 and 1 μg/L) and metabolic effects at the level of the brain, liver, serum and bile in goldfish were investigated. Abundances of mRNA transcripts coding for six feeding neuropeptides were examined to determine which may be involved in the initial neural changes associated with decreased appetite in goldfish. The 7-day fluoxetine exposure at 1 μg/L caused corticotropin-releasing factor (CRF) mRNA levels to increase by 2-fold in female hypothalamus and telencephalon, indicating that CRF may be one of the first of the feeding neuropeptides to be altered. Six hepatic miRNAs were also evaluated in the goldfish liver that were previously associated with fluoxetine exposure in zebrafish (Danio rerio). Following the 7-day exposure at 1 μg/L, miR-22b, miR-140, miR-210, miR-301a and miR-457b levels increased in the female goldfish liver by 4-6 fold. The 14-day fluoxetine exposure at 1 μg/L caused 2-fold increases in miR-210, miR-301a, miR-457b and let-7d in male goldfish liver. These miRNAs were associated with the down-regulation of anabolic metabolic pathways in zebrafish, indicating a conservation of miRNA and fluoxetine effect between fish species. Serum and bile metabolite profiles of fluoxetine exposed goldfish were evaluated using ultra performance liquid chromatography coupled to quadrupole time of flight mass spectrometry. Following the 14-day exposure at 1 μg/L, the bile metabolite profiles of male goldfish were significantly different from controls as detected by cluster analysis and fluoxetine was tentatively identified in the serum. No other discriminant metabolites were identified as of yet. The data presented suggest that fluoxetine causes metabolic disruption in goldfish at multiple organ levels. Because of the widespread detection of fluoxetine and other emerging SSRIs in the aquatic environment, future research is required to firmly establish this pharmaceutical class as a metabolic and endocrine disrupting chemical.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/32253 |
| Date | January 2015 |
| Creators | Brooke Elizabeth, Cameron |
| Contributors | Trudeau, Vance |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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