Endocrine Abstracts

Mammalian Leydig cells produce the majority of the systemic levels of the primary male sex hormone testosterone. Testosterone plays a crucial role during development of male reproductive tissues, onset of puberty, and maintaining health state. The final step of testosterone synthesis is catalyzed by 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3). Disruption of testosterone synthesis is associated with many diseases. Due to the lack of a human Leydig cell line, two different murine Leydig cell lines (MA10, BLTK1) were studied for their suitability as screening tools for testosterone synthesis disruption by xenobiotics. The endogenous expression and activity of murine 17β-HSD3 was studied in both cell lines. Further, cells were stimulated using br-8-cAMP and forskolin to study testosterone production. Cell supernatants were analyzed using LC-MS. Unstimulated cells showed no or very low endogenous 17β-HSD3 activity. Stimulated MA10 cells showed low but concentration-dependent increases of testosterone levels in supernatants after 24 h. BLTK1 cells did not produce any testosterone. This study emphasizes the necessity of analyzing steroid using sensitive MS-based methods and shows that MA10 and BLTK1 cells produce a variety of steroids but only low amounts or no testosterone.