SABNAM PARVIN, TAHSINA TABIA, URMIMALA GANGULY, ABHISHEK ROY, AVIPSA BHATTACHARYYA, GOUTAM DAS, NIRMAL GIRI, ANTARLINA SARKAR AND PRANABESH GHOSH
Abstract
Different factors in vertebrates cordially regulate sex differentiation and determination. There are certain aquatic-aerial pollutants, which are also known as Endocrine Disrupting Chemicals (EDCs), are potent regulators of sex differentiation in fishes. Repeated exposure to EDCs might negatively influence sexual as well as reproductive behaviours. Steroid hormones, certain common pollutants of air and water, environmental cues like temperature and some estrogenic mimics (fadrozole) can alter gonadal growth and differentiation. The absence of female-specific gonadal steroid estradiol- 17? (E2) congruent with androgen biosynthesis promotes sex differentiation toward male fish. A cluster of genes such as DMRT1, SOX9, SF1, AMH and steroidogenic enzymes that allow androgen synthesis undergo elevated expression in male zebra fish. Importantly, aromatase gene expression and the early steroidogenesis in fish gonads are sensitive to temperature. The development of gonads is susceptible to EDCs or pollutants, and these chemicals can modulate the production of sex- steroid hormones, thus directly affects the fish reproduction. The optimum exposure of EDCs at developmental stages can severely affect viable egg production, sperm quality and spawning rate in this species. Inhibition of the E2 synthesizing enzyme, P450 aromatase, might cause genetically female fish to show male phenotypic characters. Recently, alteration in gonadal differentiation and courtship behaviour in Zebra Fish and other teleostâs is an exciting area of research.