Journal of Endocrinology and Reproduction

R. N. Binitha ¹, S. R. Soorya ¹, C. Aruna Devi ¹, Francis Sunny ¹

Affiliations
1 Department of Zoology, University College, Palayam, Trivandrum-695034, Kerala, IN

Abstract

This study investigated the impact of sewage effluents of the polluted river, Parvathyputhenar in Trivandrum city, Kerala, India, on the activities of osmoregulatory enzymes such as Na⁺/K⁺ and Ca²⁺ ATPases, the concentration of sodium and potassium ion content in the gill and on the chloride cells (CCs) and pavement cells (PCs) that regulate ions transport in the gill epithelium of a freshwater fish. The results indicate a significant (P<0.05) decrease in the activity of branchial Na⁺/K⁺ ATPase and Ca²⁺ ATPase in the fish exposed to sewage effluents for 7, 14 and 28 days and the fish caught from the polluted river. When the fish caught from the polluted river were kept in normal pond water in the laboratory for 30, 60 and 90 days, the enzyme's activities were gradually increased and almost restored to the control level. Scanning electron microscopic analysis of gill epithelium showed noticeable changes in the surface area morphology of CCs and PCs in the fish exposed to sewage effluents. Exposure to the sewage effluents drastically altered the size and characteristic "finger print" pattern of PCs and also reduced number of CCs in the gill epithelium. As the ATPases play an important role in maintenance of functional integrity of gill epithelium it is suggested that measurement of the activities of ATPases may be used as a biomarker of exposure to sewage effluents. This work is highly pertinent in the context of increased level and effect of endocrine disrupting chemicals present in the aquatic systems, which are increasing day by day.

Keywords

Sewage Effluents, Na⁺/K⁺ ATPase, Ca²⁺ ATPase, Chloride Cells, Pavement Cells.

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C. Aruna Devi ¹, R. N. Binitha ¹, S. R. Soorya ¹, B. V. Amrutha ¹, Francis Sunny ¹

Affiliations
1 Department of Zoology, University College, Thiruvananthapuram-695034, Kerala, IN

Abstract

Bisphenol-A (BPA), an industrial chemical used to manufacture polycarbonate plastic, is considered as a potent estrogenic endocrine disruptor. A majority of xenobiotics exert their toxic effect by causing generation of reactive oxygen species, leading to oxidative stress. Reports regarding oxidative stress responses to BPA in fish are scanty. From this viewpoint, in the present study, a freshwater fish, Anabas testudineus, was exposed to sub-lethal concentrations of BPA (2.5, 5.0,&7.5 mg/l), for different time periods (7, 15&30 days). Four major enzymes of the fish's antioxidant defense system viz., catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (Se-GPx), and glutathione-S-transferase (GST), and the non-enzymatic antioxidant glutathione (GSH) were chosen as biomarkers to examine the effects of BPA. The activities of SOD, GPx and GSH were elevated to significant levels, while CAT and GST activities were decreased significantly suggesting oxidative stress in BPAexposed fish. Reactive oxygen species are known to cause DNA fragmentation. Hence, DNA fragmentation assay was also done. The severity of DNA fragmentation in fish exposed to 7.5 mg/L BPA (30days) was remarkably increased (p<0.05 vs control) and this was revealed in gel electrophoresis analysis also. The results clearly show that BPA is a pollutant with oxidative potential, also with a potential for DNA fragmentation. The potential risks of this compound to nature and human populations are significant since the production of BPA related compounds is increasing dramatically each year.

Keywords

Endocrine Disruptor, Oxidative Stress, DNA Fragmentation, BPA, Antioxidants.

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S. Reshmi ¹, V. S. Remya ¹, V. R. Anjali ¹, S. Shehna Mahim ¹, C. Aruna Devi ¹

Affiliations
1 Department of Zoology, University College, Thiruvananthapuram – 695034, Kerala, IN

Abstract

4-Nonylphenol (4-NP) is a well-known endocrine-disrupting chemical that could be present in the aquatic environment, but little is known about its oxidative stress effects. An emerging literature suggests that early life exposure to 4-NP may increase the risk of metabolic syndrome. Due to its hydrophobicity and long half-life, 4-NP can easily accumulate in living organisms, including humans, where it inflicts a series of toxic effects. In the present study, the oxidative stress and antioxidant parameters of Labeo rohita after exposure to various sub-lethal concentrations of 4-NP for 5, 10 and 15 days were examined. The level of glutathione content and the activity of glutathione peroxidase and glutathione-s-transferase were significantly inhibited, whereas the activity of superoxide dismutase, catalase and glutathione reductase and the lipid peroxidation products such as malondialdehyde and conjugated diene were significantly elevated, indicating the occurrence of oxidative stress. The results demonstrate that 4-NP in aquatic systems can affect antioxidant responses.

Keywords

Antioxidants, Endocrine-Disrupting Chemical, 4-Nonylphenol, Oxidative Stress.

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V. R. Anjali ¹, V. S. Remya ¹, S. Reshmi ¹, S. Shehna Mahim ¹, C. Aruna Devi ¹

Affiliations
1 Department of Zoology, University College, Thiruvananthapuram - 695034, Kerala, IN

Abstract

Endocrine Disrupting Chemicals (EDCs) have the potential to alter the hormonal pathways concerned with regulation of the normal homeostatic mechanisms. The adverse effects of EDCs can be observed in areas where pollution is high, particularly in aquatic ecosystems, where persistent environmental chemicals accumulate. In the present study, we investigated the endocrine disrupting effects of Bisphenol S (BPS), if any, in the levels of thyroxine, triiodothyronine, cortisol and sex steroidal [17βestradiol (E2) and testosterone(T)] hormones in juvenile as well as adult Oreochromis mossambicus. Drastic changes in serum thyroxine and triiodothyronine levels showed that BPS treatment resulted in disruption of thyroid gland function. Alteration to significant levels in serum cortisol indicated acute stress and impairment of hypothalamic-pituitaryinterrenal axis. Significant changes (p<0.05) occurred in the steroidal hormone levels which are biomarkers of endocrine disruption as they affect hypothalamic-pituitary-gonadal axis in fish. Bisphenol S also revealed estrogenic potency by inducing significant alteration in the E2/T ratio. DNA fragmentation, if any, induced by BPS was also analyzed in juvenile fish. There was no significant DNA fragmentation observed in gel electrophoresis, but a significant elevation was seen in percent fragmented DNA in the diphenylamine method. Therefore, it could be concluded that BPS at different sublethal concentrations have a profound impact on endocrine physiology of fish.

Keywords

Bisphenol S, DNA Fragmentation, Endocrine Disruption, Thyroxine, Triiodothyronine

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V. S. Remya ¹, S. Reshmi. ¹, S. Shehna Mahim ², , V. R. Anjali ¹, C. Aruna Devi ¹

Affiliations
1 Department of Zoology, University College, Thiruvananthapuram, Kerala,, IN
2 Department of Zoology, University College, Thiruvananthapuram, Kerala,

Abstract

4-Nonyl-Phenol (4-NP) is a breakdown product of Nonyl-Phenol Ethoxylate (NPE). It has attracted concern because of its persistence in the aquatic habitats and the toxicity to aquatic organisms. 4-NP is a known endocrine disruptor and a legendary xenoestrogen. Nevertheless, the non-estrogenic impacts of 4-NP in aquatic organisms have only been scarcely addressed. Hence, in the present study we evaluated the effects of sub-lethal concentrations of 4-NP (1.5, 2.0 and 2.5 µg/L) in the major carp Labeo rohita in the intermediary and mitochondrial metabolism. We found that exposure to 4-NP produced remarkable alteration in the activities of: 1. enzymes of intermediary metabolism such as glucose 6 phosphatase, lactate dehydrogenase, cytosolic malic enzyme and isocitrate dehydrogenase, and 2. mitochondrial enzymes such as malate dehydrogenase, nicotinamide adenine dinucleotide dehydrogenase, succinate dehydrogenase and cytochrome c oxidase. Thus, the study indicates that 4-NP, at concentrations as would prevail in the environment, impairs the activities of metabolic enzymes and, thereby, affects the tricarboxylic acid cycle and electron transport chain. Alteration in the levels of these enzyme activities can thus be taken to advantage for the surveillance of the impact of 4-NP in energy metabolism in the aquatic organisms.

Keywords

4-Nonylphenol, Electron Transport Chain, Intermediary Metabolism, Mitochondrial Enzymes

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