ToxSci Advance Access published online on January 5, 2005
Toxicological Sciences, doi:10.1093/toxsci/kfi077
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Biology, University of Waterloo, Ontario, Canada N2L 3G1
* To whom correspondence should be addressed. The objective of the study was to investigate the impact of aryl hydrocarbon receptor (AhR) activation on interrenal steroidogenesis in rainbow trout. To this end, fish were fed AhR agonist (ß-naphthoflavone (BNF): 10mg/kg body mass/day) and antagonist (
Received November 9, 2004
Accepted December 15, 2004
Endocrine Toxicology
Ah receptor-mediated impairment of interrenal steroidogenesis involves StAR protein and P450scc gene attenuation in rainbow trout
2 Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada N1G 2W1
Mathilakath M. Vijayan, E-mail: mvijayan{at}uwaterloo.ca
Abstract 
-naphthoflavone (ANF): 10mg/kg body mass/day) either singly or in combination (ABNF) for 5 days to elucidate the mechanisms involved in AhR-mediated depression of cortisol production. Liver AhR protein expression was significantly elevated only with ABNF, but not with BNF and ANF compared to the control group. However, all three treatments (BNF, ANF and ABNF) significantly elevated cytochrome P450 1A1 (CYP1A1) gene and protein expression in the kidney and liver, respectively, Also, these three treatment groups had significantly depressed ACTH-stimulated cortisol production in vitro compared to the control group. This attenuation of interrenal steroidogenesis corresponded with a lower mRNA abundance of steroidogenic acute regulatory (StAR) protein and cytochrome P450 cholesterol side chain cleavage enzyme (P450scc), but not 11
-hydroxylase. Furthermore, in vitro incubation of head kidney pieces with 7- [3H] pregnenolone failed to show any treatment effects on pathways downstream of P450scc, except for a significantly higher conversion to progesterone in the BNF and ANF groups. Plasma cortisol and glucose levels showed no significant change between the treated groups and control, but liver and brain glucocorticoid receptor (GR) protein expression was higher in the BNF group and ANF abolished this response. Taken together, both BNF and ANF impaired cortisol production and the mechanism may involve attenuation of StAR and P450scc, the rate limiting steps in steroidogenesis. Overall, endocrine disruption by xenobiotics acting via AhR includes impaired cortisol biosynthesis and abnormal target issue GR responses in rainbow trout.-naphthoflavone; ß-naphthoflavone; fish; salmonid; CYP1A1; cortisol; stress.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. Castillo, B. Castellana, L. Acerete, J. V Planas, F. W Goetz, S. Mackenzie, and L. Tort Stress-induced regulation of steroidogenic acute regulatory protein expression in head kidney of Gilthead seabream (Sparus aurata) J. Endocrinol., February 1, 2008; 196(2): 313 - 322. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Gravel and M. M. Vijayan Salicylate Disrupts Interrenal Steroidogenesis and Brain Glucocorticoid Receptor Expression in Rainbow Trout Toxicol. Sci., September 1, 2006; 93(1): 41 - 49. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Aluru and M. M. Vijayan Aryl Hydrocarbon Receptor Activation Impairs Cortisol Response to Stress in Rainbow Trout by Disrupting the Rate-Limiting Steps in Steroidogenesis Endocrinology, April 1, 2006; 147(4): 1895 - 1903. [Abstract] [Full Text] [PDF]
|
|