Effects of waterborne exposure to 17β-estradiol on hepatic lipid metabolism genes in tilapia (Oreochromis niloticus)

Abstract

Estradiol is a steroid hormone that regulates multiple physiological processes in teleosts. The present study aimed to investigate the role of 17β-estradiol (E2) in lipid metabolism in the liver of Nile tilapia. Waterborne exposures were performed using different concentrations of E2 (0 ng/L, 10 ng/L, 25 ng/L and 50 ng/L) and its receptor inhibitor ICI 182,780 (ICI) (1 μM/L). Subsequently, the survival rate and hepatosomatic index (HSI) of tilapia were measured and no significant changes could be found following E2 exposure. Gene expression of VLDL assembly, lipoprotein lipase and lipoprotein receptor, fatty acid uptake and triacylglycerol metabolism were detected by qPCR. E2 exposure up-regulated the expression of lipid metabolism-related genes MTP, LPL, CD36 and DGAT2. ICI exposure inhibited the level of LDLR in the liver of tilapia. This showed that E2 stimulated the MTP expression and promoted VLDL synthesis. In addition, E2 waterborne exposure induced secretion of LDLR and LPL and promoted fatty acid production. Moreover, E2 up-regulated the expression of CD36 to accelerate the transport of fatty acids. Overall, our study provides new information for evaluating Environmental estrogens (EEs) effects on farming fishes and endocrinological regulation on lipid metabolism in fish.

Keywords

• Estradiol
• Liver
• Nile tilapia
• Lipid metabolism
• Triglyceride