Thyroid hormone status and pituitary function in adult rats given oral doses of perfluorooctanesulfonate (PFOS).

Introduction: Perfluorooctanesulfonate (PFOS) is widely distributed and persistent in humans and wildlife. Prior toxicological studies have reported decreased total and free thyroid hormones in serum without a major compensatory rise in thyrotropin (TSH) or altered thyroid gland histology. Although these animals (rats, mice and monkeys) might have maintained an euthyroid state, the basis for hypothyroxinemia remained unclear.

Negative bias from analog methods used in the analysis of free thyroxine in rat serum containing perfluorooctanesulfonate (PFOS).

Decreases in serum total thyroxine (TT4) and free thyroxine (FT4) without a compensatory rise in thyroid stimulating hormone (thyrotropin or TSH) or histological changes of the thyroid have been observed in studies with perfluorooctanesulfonate (PFOS) treatments in rats. Prior observations do not fit the clinical profile of a hypothyroid state. PFOS is known to compete with fatty acids for albumin binding, and serum free fatty acids (FFA) are known to interfere with FT4 measurement using analog methods due to competition for protein binding.

A two-center international evaluation of the Immulite 2000 automated serum gastrin assay.

Objectives: To assess the performance of the Immulite 2000 serum gastrin assay.

Design And Methods: Two-center validation and comparison with two manual gastrin assays.

Results: Serum, serum separator, EDTA and heparin tube results differed <20%.