Effects of zearalenone (ZEN), deoxynivalenol (DON) and T-2 toxin (T-2) exposure on progesterone and testosterone secretion, and expression of key steroidogenic proteins in porcine Leydig cells. (A) Concentrations of progesterone and testosterone were determined using ELISA kits. (B) Protein expression of key proteins related to steroid hormone biosynthesis (StAR, CYP11A1 and 3β-HSD) were detected using Western blotting. β-actin was detected as control. Values represent means ± SEM of triplicate results. The letters a, b, and c above the bars denote significant differences between groups (p < 0.05, one-way ANOVA).