Abstract
The primary aim of this research was to develop and apply the estrogen (MMV-Luc)and androgen (TARM-Luc) responsive reporter gene assays (RGAs), previously developed by Willemsen et al. (2004), in the screening of sport supplements forendocrine disrupters (EDs). This included the development of a general extraction procedure suitable for a range of sport supplements, the validation of both bioassays,a survey of 116 sport supplement samples and the demonstration of their suitability as a routine laboratory testing tool.Validation according to Commission Decision 2002/657/EC (validation of analyticalmethods), was carried out on the estrogen and androgen RGAs coupled with sample preparation procedures as described in Chapters 3 and Chapter 4. Both these RGA sare based on mammalian breast cancer cell lines (MCF-7 and T47D) and a luciferasereporter gene. The extraction procedure was based on a dispersive solid phase extraction known as the ‘QuEChERS’ method. Validation was followed by the analysis of certified negative and positive control samples (Chapter 3) provided by the Horseracing Forensic Laboratory (HFL), UK. Consequently, the screening of 116 sport supplements available on the Island of Ireland was performed and the suitability of the developed method for the monitoring of EDs in sport supplements was proven.
The second aim of the project was to assess the risk posed to human health by the levels of estrogenic (Chapter 5) and androgenic (Chapter 6) EDs detected in the supplements. A risk assessment was performed by combining an exposure assessment study, based on the RGA results, with levels of 17p-estradiol andtestosterone shown to cause detrimental effects in animals and humans, as reported in epidemiological and animal studies within the literature. The levels of EDs detected(equivalent to 17p-estradiol and dihydrotestosterone) in the sport supplements were also compared with the acceptable daily intake (ADI) of these hormones and the amount of hormones that people are exposed to via food and water.
Finally, estrogenic EDs were divided into two categories: plant based compounds called phytoestrogens and a group of natural and synthetic estrogens (endogenoushormones and xenoestrogens). The exposure and risks connected with these two groups of estrogenic compounds were assessed separately (Chapter 5). Subsequently,the influence of genistein, a phytoestrogen most commonly present in food, on IVAbstractendogenous human blood levels of estrogen hormones (a mixture of 17|3-estradioland estrone) was investigated by two estrogenic bioassays, RGA and lowoligonucleotide DNA microarray (Chapter 7). Additionally, a comparison of these two bioassays was made as described in Chapter 7.
| Date of Award | Jul 2011 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Christopher Elliott (Supervisor) |