Effects of Environmental Contaminants and Natural Substances on Vitellogenesis in Tilapia Primary Hepatocytes

The efficacy of estrogenic chemicals and plant materials were assessed to stimulate the vitellogenin (VTG) synthesis in an in vitro system based on primary cultures of hepatocytes from female and E2-primed male Mozambique tilapia, Oreochromis mossambicus. Isolated hepatoyctes treated with nonylphenol (NP), bisphenol-A (BP), octylphenol (OP), hexachlorocyclohexane (HCH) and the combination (ALL) as endocrine-disrupting chemicals (EDCs), Solgen 40, SG40, as a commercial phytoestrogens and plant extracts (fenugreek, FG; aniseed, AS; safflower, SF; flaxseed, FS; fennel, FN; liqurice, LR; pomegranate, PG; soybean, SB) as natural substances, respectively, and their estrogenic activity were compared to control (ethanol treated hepatoyctes). Hepatic VTG levels in medium were determined by ELISA in the primary hepatocytes culture. All tested compounds induced secretion of VTG in hepatocytes of female as well as male tilapia. The induction of the hepatic response was not statistically different when each compounds was compared to control with HCH from EDCs and FG, AS, FN, LQ and PG from plant extracts in female and all cases of EDCs and plant extracts (except SG40 and SB) in male hepatoyctes. The EDCs and plant materials tested were considerably less potent than estradiol. Sensitive tilapia hepatoycte assay for measuring VTG are valuable tools for identifying the presence of environmental estrogens.