Figure 2: Scheme showing potential sites of action of EDCs on the steroidogenic machinery of Leydig cells. Inhibitory actions of EDCs on androgen biosynthesis by Leydig cells can be exerted via attenuation cAMP-PKA signaling, inhibition of cholesterol transport by the StAR/PBR complex, and suppression of expression and/or activity of different steroidogenic enzymes (e.g., 3 𝛽 HSD, P450scc, P450c17, 17 𝛽 HSD). Attenuation of functioning of one or several such target proteins by EDCs may lead to suppression of androgen production by Leydig cells and impairment of androgen-dependent physiological processes.