Estrogenic and androgenic activities in total plasma measured with reporter-gene bioassays: Relevant exposure measures for endocrine disruptors in epidemiologic studies?

Abstract

Measurements of estrogenic and androgenic activities in total plasma with Chemically Activated LUciferase gene eXpression (CALUX®) bioassays could provide biologically relevant measures for exposure to endocrine disruptors in epidemiologic studies. The objective of this study was to explore the effects of a variety of sources of potential endocrine disruptors on estrogenic and androgenic activities in total plasma measured by CALUX®. Plasma samples and interview data on sources of potential endocrine disruptors were collected from 108 men with different exposures profiles. CALUX® measurements (BioDetection Services) involved human U2-OS cell lines controlled by the estrogen receptor alpha and the androgen receptor. Mean differences (beta) in 17β-estradiol equivalents (EEQs) and dihydrotestosterone equivalents (AEQs) between exposure groups were estimated using general linear models. Mean plasma AEQs and EEQs were 9.1×10−1 ng/ml and 12.0 pg/ml, respectively. Elevated AEQs were found in smokers (beta 1.9 (95%CI 0.1–3.6)×10−1 ng/ml) and heavy drinkers (1.4 (0.2–3.1)×10−1 ng/ml), and in men occupationally exposed to disinfectants (1.6 (0.3–3.5)×10−1 ng/ml) or welding/soldering fumes (1.4 (−0.2–2.9)×10−1 ng/ml). Occupational exposure to pesticides, disinfectants, and exhaust fumes seemed to be associated with increased plasma EEQs: 1.5 (−0.2–3.2)pg/ml, 2.1 (0.2–3.9)pg/ml, and 2.9 (0.6–5.2)pg/ml, respectively. Moderate to high plasma dioxin levels, measured in a subgroup by the dioxin-responsive CALUX®, were accompanied by a 20% increase in AEQs. This is the first study in which CALUX® was used to assess hormone activities in total plasma. Although the results are not yet readily interpretable, they indicate that these measurements can be valuable for epidemiologic studies on endocrine disruptors and give direction for further research. Keywords: Biomarkers, CALUX, Endocrine disruptors, Exposure assessment, Epidemiology