- Testosterone mediates expression of the selenoprotein PHGPx by induction of spermatogenesis and not by direct transcriptional gene activation. Maiorino, M., Wissing, J.B., Brigelius-Flohé, R., Calabrese, F., Roveri, A., Steinert, P., Ursini, F., Flohé, L. FASEB J. (1998)