ABSTRACT
Aromatase P450 (P450 arom; Cyp19) is a key enzyme for vertebrate reproduction and brain development that catalyzes the conversion of androgens to estrogens. The aim of this study was to improve the knowledge on EDC effects by analysing their potential impact on brain P450 arom in adult Xenopus laevis exposed for 4 weeks to an environmental sample, the water of the river Lambro (LAM), the most polluted tributary of the Po river in North Italy. Other groups were exposed to individual compounds 10(-8) M tamoxifen (TAM), ethinylestradiol (EE2), flutamide (FLU) and methyldihydrotestosterone (MDHT) known for their (anti)estrogenic and (anti)androgenic modes of action. Expression of CYP19 was evaluated in brain extracts by quantitative RT-PCR, using a pair of primers located in the open reading frame (ORF) that allowed the simultaneous amplification of all transcripts (Aro-ORF) and a pair of primers specific for brain aromatase (Aro-B). Significant increase in Aro-ORF and Aro-B mRNA levels were observed in both females and males exposed to LAM. Different changes were observed for the model compounds using two pairs of primers. Aro-ORF mRNA expression was significantly increased in EE2 and MDHT exposed males and in FLU-exposed females, while it was significantly decreased in TAM exposed females. Aro-B mRNA was significantly increased in both sexes exposed to FLU and decreased in TAM exposed females. In conclusion, aromatase mRNA in the brain of X. laevis was regulated differentially in a gender specific manner by certain (anti)estrogenic and (anti)androgenic EDCs, supporting previous hypotheses that diverse compounds present in the river Lambro may induce feminization and demasculinization effects.
Subject(s)
Aromatase/genetics , Brain/metabolism , Endocrine Disruptors/toxicity , Gene Expression Regulation, Enzymologic , RNA, Messenger/genetics , Water Pollutants, Chemical/toxicity , Xenopus laevis/genetics , Animals , Brain/drug effects , Italy , Reverse Transcriptase Polymerase Chain Reaction , RiversABSTRACT
A wide range of environmental pollutants commonly termed endocrine disrupters (ED) can mimic steroid hormones causing adverse health effects. Recent studies showed that bisphenol A (BPA) together with other estrogenic chemicals, may be responsible for the disrupting effects observed in fish of the middle River Po. The present study has investigated the potential role of BPA in inducing this kind of effects and to this aim, 1-year-old (k1) common carp were exposed for 14 days to graded concentrations of BPA (1, 10, 100, and 1000microg/L). Histological alterations of gonads were described and compared to vitellogenin (VTG) and sex steroid levels. In carp males, BPA caused severe alterations of testis structure starting from 1microg/L. Several specimens lost the typical lobular structure showing spermatogenic cysts intermingled with free spermatozoa often degenerating into the lumen. Oocyte atresia was observed starting from 1micro BPA/L, concerning 57.1% of females at the highest concentration (1000microg BPA/L). A few carp from the same highest treatment also showed intersexuality (27%). Oestradiol-17beta (E2) significantly decreased both in 1 and 10microg BPA/L exposed carp reaching again values not significantly different from control in 1000microg BPA/L. At this concentration, a significant reduction of testosterone (T) was observed in both males and females. The mean plasma concentration of VTG significantly increased in 1000microg BPA/L exposed carp, even if a growing number of responsive carp was observed starting from the environmental concentrations (1 and 10microg BPA/L).
Subject(s)
Carps , Environmental Exposure , Phenols/toxicity , Animals , Benzhydryl Compounds , Body Weight/drug effects , Dose-Response Relationship, Drug , Estradiol/blood , Female , Gonads/anatomy & histology , Gonads/cytology , Gonads/drug effects , Male , Organ Size/drug effects , Testosterone/analogs & derivatives , Testosterone/blood , Vitellogenins/blood , Water Pollutants, Chemical/toxicityABSTRACT
The objective of this study was to correlate morphological and biochemical parameters of reproductive activity in fish exposed to graded concentrations of endocrine disrupting chemicals. Two-year-old carps were exposed for two weeks to graded concentrations of ethynyl-estradiol, tamoxifen, and flutamide. For each chemical, morphological alterations of the gonads and liver were described according to biomarker and sex steroid levels. In parallel, isolated follicular cells (FCs) and testis fragments were incubated in the presence or absence of carp pituitary homogenate and 25-hydroxycholesterol. Media were analyzed for sex steroid level evaluations.
Subject(s)
Carps/metabolism , Endocrine Disruptors/administration & dosage , Ovarian Follicle/drug effects , Testis/drug effects , Animals , Endocrine Disruptors/metabolism , Female , Gonadal Steroid Hormones/metabolism , Male , Ovarian Follicle/metabolism , Ovarian Follicle/pathology , Reproduction/drug effects , Reproduction/physiology , Testis/metabolism , Testis/pathologyABSTRACT
This study aimed to characterize the fish community in two stretches of the Po River, upstream and downstream of the Lambro River confluence, to verify the environmental effects of the presence of endocrine disrupters (EDs). More than 5000 specimens were captured, identified at the species level, and recorded for biometric parameters. Plasma, liver, and gonad fragments were sampled for histological and biochemical analyses. Few specimens belonging to carp and barbel showed gonads with the concomitant presence of male and female tissues and altered plasma levels of vitellogenin and sex steroids; thus, these species will be considered for successive environmental studies.
