Detection and analysis of 17 steroid hormones by ultra-high-performance liquid chromatography-electrospray ionization mass spectrometry (UHPLC-MS) in different sex and maturity stages of Antarctic krill (Euphausia superba Dana).

Xiangning Han,Daicheng Liu,Muhammad Hanif

doi:10.1371/journal.pone.0213398

Abstract

A sensitive and accurate method for determination of 17 endogenous and exogenous steroid hormones in Antarctic krill was developed. The method utilized UHPLC-MS in electrospray ionization mode (ESI). Samples were prepared by alkaline hydrolysis; sequential vortex extraction with ethyl acetate, methanol and acetonitrile; followed by a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) clean-up method. The system suitability tests including theoretical plate number, resolution, repeatability, tailing factor proved the system’s resolution and reproducibility that can meet the requirements of sample analysis. The developed method resulted in satisfactory recoveries that varied from 75.4%-110.6% and relative standard deviations (RSDs) that ranged from 3.1%-10.5%. The ranges of the limits of detection (LODs) and the limits of quantitation (LOQs) were 2–30 ng kg-1 and 10–100 ng kg-1, respectively. 14 hormones including cortisone, aldosterone, testosterone propionate, estriol, megestrol acetate, cortisone acetate, dexamethasone, testosterone, hydroxyprogesterone, nandrolone, prednisolone, cortisol, progesterone and estradiol were found in Antarctic krill. Other 3 hormones (Diethylstilbestrol, norethisterone and androsterone) were not detected. The levels of exogenous steroid hormones were much greater than those of endogenous steroid hormones, and the levels of exogenous glucocorticoids were much greater than those of exogenous sex hormones. The changes of hormones in different sex and maturity stages were also explored. Endogenous hormones might regulate the reproductive and development of Antarctic krill. The detected exogenous hormones suggests the potential for hormonal contamination in Antarctic waters that can affect organisms even affect human beings by food chain.

Highlights

Antarctic krill, Euphausia superba, a swarming Euphausiid crustacean, is a keystone species of the Antarctic sea ice ecosystem and a commercially valuable species [1]
The physiological activities of Antarctic krill including synthesis of active substances, growth, development, reproduction even swarming may be regulated by hormones similar with other crustaceans, but little is known about endogenous hormones in Antarctic krill
Ionization electrospray ionization mode (ESI) sources occur in the solution state, so the composition of the mobile phase has a significant influence on the response of the solute

Summary

Introduction

Euphausia superba, a swarming Euphausiid crustacean, is a keystone species of the Antarctic sea ice ecosystem and a commercially valuable species [1]. Antarctic krill contains high quality lipid and protein that can be used in a variety of functional foods [2]. The study of active substances in Antarctic krill has included the measurement of lipids, proteins, and enzymes [3,4,5,6]. Studies of crustaceans have shown that the synthesis and metabolism of these substances are regulated by endogenous hormones [7,8,9]. The physiological activities of Antarctic krill including synthesis of active substances, growth, development, reproduction even swarming may be regulated by hormones similar with other crustaceans, but little is known about endogenous hormones in Antarctic krill. It is of great significance to study endogenous and exogenous steroid hormones in Antarctic krill

Methods

Results

Conclusion