Oestrogenic and (anti)androgenic activity of zearalenone and its metabolites in two in vitro yeast bioassays

Selected resorcylic acid lactones (RALs) – zearalenone (ZEA), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL) were investigated for their oestrogenic and (anti)androgenic activity using two in vitro RIKILT yeast Estrogen and Androgen bioAssays. Our results show that all tested compounds are able to induce hERα-dependent transcription and the rank of their potencies, based on EC50 values is as follows: α-ZOL > α-ZAL > ZEA > β-ZAL > β-ZOL. None of the tested compounds appeared to be androgenic when tested individually at concentrations ranging from 0.1 pM to 0.1 mM. However, all RALs inhibited 17β-testosterone-induced transcriptional activity. The highest antiandrogenic potential showed α-ZOL, β-ZAL and β-ZOL with the IC50 of 6.2 μM, 11.5 μM and 15.2 μM, respectively. When compared with flutamide, for which a relative antiandrogenic potency (RAAP) was assumed as 100%, the corresponding RAAPs for α-ZOL, β-ZAL and β-ZOL were 220, 119 and 89.8%, respectively. In summar...