Regulation of gonadal sex ratios and pubertal development by the thyroid endocrine system in zebrafish (Danio rerio)

Developmental timing of sodium perchlorate exposure alters angiogenesis, thyroid follicle proliferation and sexual maturation in stickleback

“…Perchlorate may alter the rate of gametogenesis in both sexes. Sharma and Patiño (2013) described a greater proportion of late stage testes in 60 dpf male zebrafish along with a greater proportion of early stage oocytes in female zebrafish exposed to 100 mg/L sodium perchlorate. The temporal differences of exposure between the present study, Petersen et al (2015), and Sharma and Patiño (2013) make comparisons difficult, but together these studies provide convincing evidence that perchlorate can alter gamete maturation in fish.…”

“…Thyroid hormone receptors are present on teleost ovarian and testicular cells (Nelson and Habibi 2009) and goitrogens affect gonadal development in fishes including increased numbers of Sertoli and germ cells in tilapia ( Oreochromis niloticus ) exposed to thiouracil (PTU) (Matta et al, 2002) and impaired testicular and ovarian recrudescence in catfish ( Clarias gariepinus ) exposed to thiourea (Supriya et al, 2005; Swapna et al, 2006). Perchlorate causes a female bias in the sex ratio of zebrafish (Mukhi et al, 2007a; Sharma and Patiño, 2013), while evidence of masculinization was found in stickleback (Bernhardt et al, 2006). A critical window for sex determination in stickleback was determined to be within the first 14 days post hatch (dph) (Hahlbeck et al, 2004).…”

Introduction to Special Issue: Disruption of thyroid, sex steroid, and adrenal hormone systems and their crosstalk in aquatic wildlife

“…Working with amphibians, Mathieu-Denoncourt et al (2015b) present evidence for paradoxical effects of both moderate (11 wk) and long term (51 wk) exposure to the plasticizer, monomethyl phthalate during development in Western clawed frogs (Silurana tropicalis), whereby it promoted rather than inhibited metamorphosis and also resulted in male-biased populations. While a comparison with Zebrafish was not made in the study of Mathieu-Denoncourt et al (2015b), it is interesting that their observations with S. tropicalis are similar to those with Zebrafish made experimentally hyperthyroid (Mukhi et al, 2007;Sharma and Patiño, 2013).…”

“…More recently, von Hippel and colleagues showed that exposure to the thyroid hormone synthesis inhibitor, perchlorate, leads to hermaphroditism in Threespine Stickleback (Gasterosteus aculeatus) (Bernhardt et al, 2006), while Patiño and colleagues found that hypo-and hyperthyroidism leads to female-and male-skewed populations of Zebrafish (Danio rerio), respectively (Mukhi et al, 2007;Sharma and Patiño, 2013). In this issue, Furin et al (2015a) extend on this work by reporting that perchlorate has greater and much longer-lasting effects on thyroid and gonadal condition of G. aculeatus when exposures occur early during development.…”

Assessing reproductive and endocrine parameters in male largescale suckers (Catostomus macrocheilus) along a contaminant gradient in the lower Columbia River, USA

“…Although the thyroid endocrine system plays a role in gonadal development and reproduction of teleosts (Cyr and Eales, 1996), the effects of thyroid endocrine disruption on reproductive fitness have been difficult to document (Brown et al, 2004;Carr and Patiño, 2011). Recent studies with zebrafish have indicated a relationship between the status of the thyroid endocrine system and gonadal sex differentiation, pubertal development, and reproduction Sharma and Patiño, 2013). Specifically, Torres et al (2013) showed that although thyroid condition and pubertal development were not affected by concentrations of BDE-47, growth during the juvenile-to-adult transition was affected, especially in males.…”