2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) decreases progesterone synthesis through cAMP-PKA pathway and P450scc downregulation in mouse Leydig tumor cells.

Polybrominated diphenyl ethers (PBDEs) are commonly used as flame retardants in textiles, plastics and electronics and represent a group of persistent environmental contaminants. They have been found to accumulate in human and marine mammals. Previous studies have shown that PBDEs have endocrine-disrupting properties and reproductive toxicity. However, the mechanisms under the reproductive disruptions are still not well understood. In this study, we explored the effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on progesterone biosynthesis and possible mechanisms in mouse Leydig tumor cells (mLTC-1). Our results showed that BDE-47 could reduce progesterone production and decrease the intracellular cAMP level induced by hCG or forskolin. These suggested that BDE-47 decreasing progesterone production in mLTC-1 cells may be associated with the decline of intracellular cAMP level. Moreover, our data also indicated that the site G protein in cAMP-PKA pathway may be involved in this process. Furthermore, the addition of cAMP analog, 8-Br-cAMP, could not reverse the decrease of progesterone biosynthesis, indicating that a post-cAMP site (or sites) might be involved into the BDE-47-decreased progesterone production. In addition, we found BDE-47 reduced the activity of P450 side chain cleavage enzyme (P450scc), which was companied with the decline of P450scc mRNA and protein level in mLTC-1 cells. Put all together, these results suggested that progesterone synthesis decrease induced by BDE-47 may be associated with attenuation of cAMP generation and reduction of P450scc activity.