Diesel exhaust particles suppress expression of sex steroid hormone receptors in TM3 mouse Leydig cells

Murine Leydig TM3 cells, derived from mouse testis, were exposed to diesel exhaust particles (DEP) and DEP components for 24 h. mRNA expression of estrogen receptor (ER) α and CYP1A1 were then measured by real-time PCR. Exposure to DEP (10 μg/ml) reduced ERα mRNA expression by approximately 50% and increased P450 1A1 mRNA expression by approximately fivefold. Cycloheximide (CHX), an inhibitor of protein synthesis, abolished the DEP-induced effects on ERα mRNA expression. Thus, protein synthesis mediated the DEP-induced reduction of ERα mRNA expression.