Estrogen receptors in dolphin kidney endothelial cells : Detection and comparison with estrogen receptors from MCF-7 cells

Cell lines acceptable for toxicological evaluation of terrestrial mammals, including humans, have been available for some time; however, long-term, well-characterized cell lines have not generally been available for marine mammals, particularly the Cetacea. We initiated an epithelial cell line from neonate kidney tissues of the Atlantic bottlenose dolphin, Tursiops truncatus. These cells have been karyotyped and evaluated for induction of hydrocarbon metabolism, formation of DNA adducts, and DNA excision repair. We compared the dolphin cell line, DK1, with the human cell line MCF-7, characterizing the DK1 estrogen receptor (ER) as to 17β-estradiol (E2) binding, quantity of ER per cell, and the capacity of DK1 cells induced by 2,3,7,8-tetrachlorodibenzo(p)dioxin (TCDD, dioxin) or E2 to metabolize benzo(a)pyrene (BaP). DK1 cells exhibited less ER than MCF-7 cells and showed decreased affinity of E2 binding to ER compared with MCF-7 cells. DK1 cells exhibited greater capacity to metabolize BaP than MCF-7 cells, a probable reflection of the low levels of aryl hydrocarbon receptor (AhR) expression in MCF-7. Treatment of DK1 cells with TCDD or E2 increased metabolism of BaP to a variety of metabolites that differed between the inducing agents. DK1 cells exhibit AhR and steroidal, including ER, receptors that make them useful for in vitro toxicological evaluations of cetacean tissues and cells.