The effects of levonorgestrel application in different dose and periods on antioxidative metabolism of Zebra fish (Danio rerio, Hamilton, 1822)

In this study, the application of Levonorgestrel (LNG), one of the synthetic progestins classified as an endocrine disrupting chemical and known to have effects on reproductive physiology particularly in fish, nonetheless, whose metabolites are thought to act like xenobiotics in the ecosystem, in different doses and durations, on antioxidative metabolism in Zebra fish were investigated. Fish were exposed to two LNG as low (0.312 µg/L) and high (6.24 µg/L) doses for 24, 48 and 96 hours. At this stage, the static test method of acute bio-assay, was applied and the experiments were carried out in triplicate. Subsequently the experiment plan was performed, muscle and liver tissue samples were collected by dissecting the fish. In these samples, antioxidant enzyme activity and lipid peroxidation level were measured by SOD, CAT, GPx and MDA analysis, respectively. For this study, it was determined that enzyme activity values were affected by LNG dose administration, however the differences determined as a result of the statistical evaluation were found insignificant (p≤0,05). High-dose application had an effect on the SOD enzyme activity value with increasing application time and caused an accelaeration in the values in terms of both tissues, CAT enzyme activity values fluctuated particularly the values obtained from the high-dose applied groups, and GPx enzyme activity values were observed in high-dose LNG application, demonstrated high activity especially in the liver. According to the results of the MDA, low-dose LNG application in liver tissue showed a decrease compared to muscle tissue, whereas similar values were determined at high doses. In this sense, liver tissue was found more sensitive to LNG application compared to muscle tissue and a better indicator for oxidative stress.