Effects of Ammonium Perchlorate on Thyroid Function in Developing Fathead Minnows, Pimephales promelas

Abstract

Perchlorate is a known environmental contaminant, largely due to widespread military use as a propellant. Perchlorate acts pharmacologically as a competitive inhibitor of thyroidal iodide uptake in mammals, but the impacts of perchlorate contamination in aquatic ecosystems and, in particular, the effects on fish are unclear. Our studies aimed to investigate the effects of concentrations of ammonium perchlorate that can occur in the environment (1, 10, and 100 mg/L) on the development of fathead minnows, Pimephales promelas. For these studies, exposures started with embryos of < 24-hr postfertilization and were terminated after 28 days. Serial sectioning of thyroid follicles showed thyroid hyperplasia with increased follicular epithelial cell height and reduced colloid in all groups of fish that had been exposed to perchlorate for 28 days, compared with control fish. Whole-body thyroxine (T4) content (a measure of total circulating T4) in fish exposed to 100 mg/L perchlorate was elevated compared with the T4 content of control fish, but 3,5,3′-triiodothyronine (T3) content was not significantly affected in any exposure group. Despite the apparent regulation of T3, after 28 days of exposure to ammonium perchlorate, fish exposed to the two higher levels (10 and 100 mg/L) were developmentally retarded, with a lack of scales and poor pigmentation, and significantly lower wet weight and standard length than were control fish. Our study indicates that environmental levels of ammonium perchlorate affect thyroid function in fish and that in the early life stages these effects may be associated with developmental retardation.

Outdoor dissolution of detonation residues of three insensitive munitions (IM) formulations

“…Although NTO has low mammalian toxicity (London and Smith, 1985) both NTO and DNAN can form toxic transformation products (Le Campion et al, 1999;Davies and Provatas, 2006). AP is known to interfere with iodine uptake and so affects thyroid function (Motzer, 2001;Crane et al, 2005).…”

Chronic perchlorate exposure impairs stickleback reproductive behaviour and swimming performance

“…The effects of perchlorate on thyroid histology and thyroid hormone synthesis are well established (Miranda et al, 1996;York et al, 2001aYork et al, ,b, 2003Patiño et al, 2003;McNabb et al, 2004;Bradford et al, 2005;Crane et al, 2005;Park et al, 2006). Perchlorate is an endocrine disrupting toxicant known to interfere with thyroid hormone production by competitively inhibiting the ability of sodium-iodide symporters to transport iodide into thyroid follicles, which in turn reduces thyroid hormone synthesis (NRC, 2005).…”

“…Perchlorate is an endocrine disrupting toxicant known to interfere with thyroid hormone production by competitively inhibiting the ability of sodium-iodide symporters to transport iodide into thyroid follicles, which in turn reduces thyroid hormone synthesis (NRC, 2005). Many studies describe histological effects of perchlorate exposure, such as hypertrophied thyroid follicular cells (York et al, 2001a,b;Patiño et al, 2003;McNabb et al, 2004;Bradford et al, 2005;Park et al, 2006), but few have addressed perchlorate's effects on life history characteristics, such as reproductive behaviour (York et al, 2001b(York et al, , 2003Crane et al, 2005). What few studies exist primarily document the number of mounting attempts during mice reproduction (York et al, 2001a) or fertility/fecundity parameters (York et al, 2001b;Wibe et al, 2002;Patiño et al, 2003).…”

Science and environmental risk: the case of perchlorate contamination in California

“…Failure of the body to provide enough of these hormones (especially T3) in developing infants can result in hypothyroidism, cretinism and brain developmental disorders (Wolff, 1998;NRC, 2005). Even low levels of perchlorate may results in lower IQ levels in children (de Escobar et al, 2000;Sharp & Walker, 2001), although such subtle effects may be multicausal and are difficult to substantiate fully (Crane et al, 2005).…”