Efeitos comportamentais e endócrinos da exposição na fase embrionária ao etonogestrel em peixe-zebra

Abstract

Improper disposal of expired drugs directly into the garbage or sewage systems without specific treatment increases concentration of these components in wastewater. Waste from pharmaceutical industries, used in research and treated animal waste can contribute to this problem. Several studies have already confirmed the interference of these compounds in embryonic growth and development, altering the behavior of exposed species and even causing endocrine, hormonal or even genetic alterations. With use of progestins for various purposes in human and veterinary medicine, the appearance of their residues in natural waters has been reported. The exposure of these animals can negatively affect their sexual development, leading to alterations such as intersex induction or changes in the proportion of males and females. Etonogestrel (ETO) is a compound derived from 19- nortestosteron, but it can also be found commercially in the form of a contraceptive implant. However, few studies have evaluated its possible effects on non-target organisms in aquatic environments, such as fish. In this study, was evaluated whether exposure to ETO in the early stages of development causes hormonal and behavioral changes in zebrafish larvae. In this study, embryos were exposed to 3.2 ng/L of ETO in the first five days post-fertilization. Exposed larvae showed behavioral changes that characterize anxiety and fear-like behavior, and also showed an increase in stress hormone levels. These results show that accidental exposure to ETO can alter the natural behavior of fish and other non-target organisms, leaving them susceptible to predators and other threats in the aquatic environment.