(1) State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
WOS标题词:
Science & Technology
; Life Sciences & Biomedicine
类目[WOS]:
Environmental Sciences
研究领域[WOS]:
Environmental Sciences & Ecology
摘要:
Thyroid hormones (THs) play an important role in the normal development and physiological functions
in fish. Environmental chemicals may adversely affect thyroid function by disturbing gene transcription.
Perfluorooctane sulfonate (PFOS), a persistent compound, is widely distributed in the aquatic environment
and wildlife. In the present study, we investigated whether PFOS could disrupt the hypothalamic–
pituitary–thyroid (HPT) axis. Zebrafish embryos were exposed to various concentrations of PFOS
(0, 100, 200 and 400 lg L 1) and gene expression patterns were examined 15 d post-fertilization. The
expression of several genes in the HPT system, i.e., corticotropin-releasing factor (CRF), thyroid-stimulating
hormone (TSH), sodium/iodide symporter (NIS), thyroglobulin (TG), thyroid peroxidase (TPO), transthyretin
(TTR), iodothyronine deiodinases (Dio1 and Dio2) and thyroid receptor (TRa and TRb), was
quantitatively measured using real-time PCR. The gene expression levels of CRF and TSH were significantly
up-regulated and down-regulated, respectively, upon exposure to 200 and 400 lg L 1 PFOS. A significant
increase in NIS and Dio1 gene expression was observed at 200 lg L 1 PFOS exposure, while TG
gene expression was down-regulated at 200 and 400 lg L 1 PFOS exposure. TTR gene expression was
down-regulated in a concentration-dependent manner. Up-regulation and down-regulation of TRa and
TRb gene expression, respectively, was observed upon exposure to PFOS. The whole body thyroxine
(T4) content remained unchanged, whereas triiodothyronine (T3) levels were significantly increased,
which could directly reflect disrupted thyroid hormone status after PFOS exposure. The overall results
indicated that PFOS exposure could alter gene expression in the HPT axis and that mechanisms of disruption
of thyroid status by PFOS could occur at several steps in the synthesis, regulation, and action of thyroid
hormones.
英文摘要:
Thyroid hormones (THs) play an important role in the normal development and physiological functions in fish. Environmental chemicals may adversely affect thyroid function by disturbing gene transcription. Perfluorooctane sulfonate (PFOS), a persistent compound, is widely distributed in the aquatic environment and wildlife. In the present study, we investigated whether PFOS could disrupt the hypothalamic-pituitary-thyroid (HPT) axis. Zebrafish embryos were exposed to various concentrations of PFOS (0, 100, 200 and 400 mu g L-1) and gene expression patterns were examined 15 d post-fertilization. The expression of several genes in the HIPT system, i.e., corticotropin-releasing factor (CRF), thyroid-stimulating hormone (TSH), sodium/iodide symporter (NIS), thyroglobulin (TG), thyroid peroxidase (TPO), transthyretin (TTR), ioclothyronine deiodinases (Dio1 and Dio2) and thyroid receptor (TR alpha and TR beta), was quantitatively measured using real-time PCR. The gene expression levels of CRF and TSH were significantly up-regulated and down-regulated, respectively, upon exposure to 200 and 400 mu g L-1 PFOS. A significant increase in NIS and Diol gene expression was observed at 200 mu g L-1 PFOS exposure, while TG gene expression was down-regulated at 200 and 400 mu g L-1 PFOS exposure. TTR gene expression was down-regulated in a concentration-dependent manner. Up-regulation and down-regulation of TR alpha and TR beta gene expression, respectively, was observed upon exposure to PFOS. The whole body thyroxine (T-4) content remained unchanged, whereas triiodothyronine (T-3) levels were significantly increased, which could directly reflect disrupted thyroid hormone status after PFOS exposure. The overall results indicated that PFOS exposure could alter gene expression in the HPT axis and that mechanisms of disruption of thyroid status by PFOS could occur at several steps in the synthesis, regulation, and action of thyroid hormones. (C) 2009 Elsevier Ltd. All rights reserved.
