A rapid screening test for endocrine disrupting chemicals using primary cell culture of the marine medaka.

While endocrine disrupting chemicals (EDCs) pose a significant threat to wildlife worldwide, their diverse chemical structures present a major challenge to their detection, particularly since they are present at very low concentrations in the environment. We here report the development of an in vitro system for rapid screening of EDCs, using primary cell cultures (pituitary, ovarian follicular and testicular cells) of the marine medaka (Oryzias melastigma). Pituitary, testis and ovary cell cultures were developed and challenged by environmentally relevant concentrations of three well known EDCs (viz. estradiol, 2,2',4,4'-tetrabromodiphenyl ether, and 4-n-nonylphenol) as well as hypoxia (which has been shown to be a potent endocrine disruptor). In general, the mRNA expression levels of gonadotropins, their receptors and steroidogenic enzymes exhibited dose response relationships to the four endocrine disruptors in different tissues. The sensitivity and responses were also comparable to in vivo responses of whole fish and in vitro responses of the H295R human adrenocortical cell line. Our results suggest that the use of marine medaka primary cultured cells can serve as a cost effective tool for rapid screening of EDCs in the marine environment, and at the same time, sheds light on the underlying mechanisms of EDCs by deciphering their specific target sites along the hypothalamus-pituitary-gonad axis of vertebrates.