کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2800067 1568895 2015 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Perchlorate disrupts embryonic androgen synthesis and reproductive development in threespine stickleback without changing whole-body levels of thyroid hormone
ترجمه فارسی عنوان
پرکلرات متلاشی می شود سنتز آندروژن جنینی و توسعه تولید مثل در لایه بیضه سه تایی بدون تغییر سطح کل بدن از هورمون تیروئید
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی علوم غدد
چکیده انگلیسی


• Long-term exposure to perchlorate does not affect whole-body thyroid hormone levels in stickleback except at the lowest dose.
• Perchlorate affects thyroid morphological development in a manner consistent with hormonal compensation.
• Gonad development in both males and females is affected.
• Our results suggest both thyroidal and non-thyroidal mechanisms of perchlorate action.

Perchlorate, an environmental contaminant, disrupts normal functioning of the thyroid. We previously showed that perchlorate disrupts behavior and gonad development, and induces external morphological changes in a vertebrate model organism, the threespine stickleback. Whether perchlorate alters these phenotypes via a thyroid-mediated mechanism, and the extent to which the effects depend on dose, are unknown. To address these questions, we chronically exposed stickleback to control conditions and to three concentrations of perchlorate (10, 30 and 100 ppm) at various developmental stages from fertilization to reproductive maturity. Adults chronically exposed to perchlorate had increased numbers of thyroid follicles and decreased numbers of thyrocytes. Surprisingly, T4 and T3 levels in larval, juvenile, and adult whole fish chronically exposed to perchlorate did not differ from controls, except at the lowest perchlorate dose, suggesting a non-monotonic dose response curve. We found no detectable abnormalities in external phenotype at any dose of perchlorate, indicating that the increased number of thyroid follicles compensated for the disruptive effects of these doses. In contrast to external morphology, gonadal development was altered substantially, with the highest dose of perchlorate causing the largest effects. Perchlorate increased the number both of early stage ovarian follicles in females and of advanced spermatogenic stages in males. Perchlorate also disrupted embryonic androgen levels. We conclude that chronic perchlorate exposure may not result in lasting adult gross morphological changes but can produce lasting modifications to gonads when compensation of T3 and T4 levels occurs by thyroid follicle hyperplasia. Perchlorate may therefore affect vertebrate development via both thyroidal and non-thyroidal mechanisms.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: General and Comparative Endocrinology - Volume 210, 1 January 2015, Pages 130–144
نویسندگان
, , , , , , , ,