Nanoparticle-rich diesel exhaust may disrupt testosterone biosynthesis and metabolism via growth hormone

摘要: Abstract We previously reported that exposure to low (22.5 ± 0.2 nm in diameter, 15.4 ± 1.0 μg/m3 mass weight, 2.27 × 105/cm3 mean number concentration), and medium (26.1 ± 0.5 nm, 36.4 ± 1.2 μg/m3, 5.11 × 105/cm3) concentrations of nanoparticle-rich diesel exhaust (NR-DE) for 1 2 months (5 h/day, 5 days/week) significantly increased plasma testosterone male Fischer 344 rats, whereas a high concentration (27.1 ± 0.5 nm, 168.8 ± 2.7 μg/m3, 1.36 × 106/cm3) did not. The present study attempts clarify the mechanism this elevation. Low exposures NR-DE steroidogenic acute regulatory protein (StAR)- cytochrome P450 side-chain cleavage (P450scc)-mRNA their expressions testis which elevation pattern was very similar levels. Interestingly, both levels month growth hormone (GH) receptor expression testis, also testicular insulin-like factor I-mRNA hepatic microsomal 2C11-mRNA rats. These two factors are thought be related secretion. Disruption biosynthesis by may mode action reproductive toxicity, may, part, regulated increasing StAR P450scc via GH signalling.