ABSTRACT
Previous studies in rats have indicated that a diet enriched with Bisphenol A adversely effects metabolism and reproductive success. In rats exposed to BPA by maternal gavage, alteration in the developmental programming, higher obesity rates and reproductive anomalies were induced. Starting with this evidence, the aim of this study was to provide important insights on the effects induced by a BPA enriched diet, on the reproductive physiology and metabolism of juvenile fish, simulating the scenario occurring when wild fish fed on prey contaminated with environmental BPA. Seabream was chosen as model, as it is one of the primary commercial species valued by consumers and these results could provide important findings on adverse effects that could be passed on to humans by eating contaminated fish. A novel method for measuring BPA in the food and water by affinity chromatography was developed. Analysis of signals involved in reproduction uncovered altered levels of vtg and Zp, clearly indicating the estrogenic effect of BPA. Similarly, BPA up-regulated catd and era gene expression. A noteworthy outcome from this study was the full length cloning of two vtg encoding proteins, namely vtgA and vtgB, which are differently modulated by BPA. Cyp1a1 and EROD activity were significantly downregulated, confirming the ability of estrogenic compounds to inhibit the detoxification process. GST activity was unaffected by BPA contamination, while CAT activity was down regulated. These results collectively confirm the estrogenic effect of BPA and provide additional characterization of novel vtg genes in Sparus aurata.
Subject(s)
Benzhydryl Compounds/toxicity , Chemical and Drug Induced Liver Injury/veterinary , Endocrine Disruptors/toxicity , Fish Diseases/chemically induced , Food Contamination , Liver/drug effects , Phenols/toxicity , Sea Bream , Amino Acid Sequence , Animal Feed/adverse effects , Animals , Aquaculture , Benzhydryl Compounds/administration & dosage , Biomarkers/chemistry , Biomarkers/metabolism , Chemical and Drug Induced Liver Injury/metabolism , Dose-Response Relationship, Drug , Egg Proteins/genetics , Egg Proteins/metabolism , Endocrine Disruptors/administration & dosage , Fish Diseases/metabolism , Fish Proteins/agonists , Fish Proteins/chemistry , Fish Proteins/genetics , Fish Proteins/metabolism , Gene Expression Regulation, Developmental/drug effects , Liver/growth & development , Liver/metabolism , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Molecular Sequence Data , Phenols/administration & dosage , Protein Isoforms/agonists , Protein Isoforms/chemistry , Protein Isoforms/genetics , Protein Isoforms/metabolism , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism , Sequence Alignment , Sequence Homology, Amino Acid , Vitellogenins/agonists , Vitellogenins/chemistry , Vitellogenins/genetics , Vitellogenins/metabolism , Zona Pellucida GlycoproteinsABSTRACT
Glucocorticoids (GCs) modulate many cellular processes through the binding of the glucocorticoid receptor (GR) to specific responsive elements located upstream of the transcription starting site or within an intron of GC target genes. Here we describe a transgenic fish line harboring a construct with nine GC-responsive elements (GREs) upstream of a reporter (EGFP) coding sequence. Transgenic fish exhibit strong fluorescence in many known GC-responsive organs. Moreover, its enhanced sensitivity allowed the discovery of novel GC-responsive tissue compartments, such as fin, eyes, and otic vesicles. Long-term persistence of transgene expression is seen during adult stages in several organs. Pharmacological and genetic analysis demonstrates that the transgenic line is highly responsive to drug administration and molecular manipulation. Moreover, reporter expression is sensitively and dynamically modulated by the photoperiod, thus proving that these fish are an in vivo valuable platform to explore GC responsiveness to both endogenous and exogenous stimuli.
