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EFFECTS OF PERFLUOROOCTANE SULFONATE (PFOS) ON MATERNAL AND DEVELOPMENTAL THYROID STATUS IN THE RAT
Citation:
Thibodeaux, J R., R. G. Hanson, B E. Grey, J M. Rogers, AND C S. Lau. EFFECTS OF PERFLUOROOCTANE SULFONATE (PFOS) ON MATERNAL AND DEVELOPMENTAL THYROID STATUS IN THE RAT. Presented at NC Society of Toxicology, RTP, NC, March 02, 2002.
Description:
EFFECTS OF PERFLUOROOCTANE SULFONATE (PFOS) ON MATERNAL AND DEVELOPMENTAL THYROID STATUS IN THE RAT. JR Thibodeaux1, R Hanson1, B Grey1, JM Rogers1, ME Stanton2, and C Lau1. 1Reproductive Toxicology Division; 2Neurotoxicology Division, NHEERL, ORD, US EPA, Research Triangle Park, NC.
PFOS, a compound in a class of organic fluorochemicals that is used in the manufacture of surfactants and insecticides, is a ubiquitous environmental contaminant which has been recently found to be a developmental toxicant in laboratory rodents. The focus of our work is to ascertain if alterations of thyroid status are involved in PFOS toxicity. Timed-pregnant, Sprague-Dawley rats were given 1, 2, 3, or 5 mg/kg/day PFOS/K+ by oral gavage from gestational day (GD) 2-21; controls received 0.5% Tween-20 vehicle (1 ml/kg). Blood samples were collected from the dams on GD 21 and from the pups throughout postnatal development. Serum TSH, total and free T4, and T3 levels were determined by radioimmunoassay at all doses in the dams and up to the 3 mg/kg dose in the offspring. Total and free T4 as well as T3 levels in PFOS-treated dams were significantly lower than in controls, but the TSH level was not affected. Hypothyroxinemia was observed in the PFOS-exposed pups during the pre-weaning period. Because of the critical roles of thyroid hormones in brain development, evaluation of a neurochemical marker (choline acetyltransferase, ChAT) and a behavioral test (T-maze delayed alternation) for learning and memory were conducted in weanlings exposed prenatally to 3 mg/kg/day PFOS to corroborate with the PFOS-induced changes of thyroid status. Despite the T4 reduction, no significant alterations in hippocampal or cortical ChAT activity or T-maze performance were observed in these pups. Our results indicate that PFOS exposure alters the thyroid status of pregnant rats and their offspring, but this hormonal imbalance is not sufficient to produce corresponding changes in the measured neurochemical and behavioral markers. [This abstract does not reflect EPA policy.]