Nitrophenols isolated from diesel exhaust particles regulate steroidogenic gene expression and steroid synthesis in the human H295R adrenocortical cell line
- Department of Basic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193 (Japan)
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509 (Japan)
- Environmental Nanotoxicology Section, Research Center for Environmental Risk, National Institute for Environmental Studies, Tsukuba (Japan)
Studies of nitrophenols isolated from diesel exhaust particles (DEPs), 3-methyl-4-nitrophenol (PNMC) and 4-nitro-3-phenylphenol (PNMPP) have revealed that these chemicals possess estrogenic and anti-androgenic activity in vitro and in vivo and that PNMC accumulate in adrenal glands in vivo. However, the impacts of exposure to these compounds on adrenal endocrine disruption and steroidogenesis have not been investigated. To elucidate the non-receptor mediated effects of PNMC and PNMPP, we investigated the production of the steroid hormones progesterone, cortisol, testosterone, and estradiol-17{beta} and modulation of nine major enzyme genes involved in the synthesis of steroid hormones (CYP11A, CYP11B1, CYP17, CYP19, 17{beta}HSD1, 17{beta}HSD4, CYP21, 3{beta}HSD2, StAR) in human adrenal H295R cells supplied with cAMP. Exposure to 10{sup -7} to 10{sup -5} M PNMC and 1 mM 8-Br-cAMP for 48 h decreased testosterone, cortisol, and estradiol-17{beta} levels and increased progesterone secretion. At 10{sup -5} M, PNMC with 1 mM 8-Br-cAMP significantly stimulated expression of the 17{beta}HSD4 and significantly suppressed expression of 3{beta}HSD2. In comparison, 10{sup -7} to 2 x 10{sup -5} M PNMPP with 1 mM 8-Br-cAMP for 48 h decreased concentrations of estradiol-17{beta}, increased progesterone levels, but did not affect testosterone and cortisol secretion due to the significant suppression of CYP17 and the non-significant but obvious suppression of CYP19. Our results clarified steroidogenic enzymes as candidates responsible for the inhibition or stimulation for the production of steroid hormones in the steroidogenic pathway, thus providing the first experimental evidence for multiple mechanisms of disruption of endocrine pathways by these nitrophenols.
- OSTI ID:
- 21140846
- Journal Information:
- Toxicology and Applied Pharmacology, Vol. 229, Issue 1; Other Information: DOI: 10.1016/j.taap.2008.01.026; PII: S0041-008X(08)00054-9; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
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