Changes in thyroid peroxidase activity in response to various chemicals

Area of Science:

• Endocrinology
• Environmental Toxicology
• Biochemistry

Background:

• Thyroid hormone (TH) synthesis is crucial for human health and relies on thyroperoxidase (TPO) activity.
• Disruption of the TH axis by environmental chemicals is a significant public health concern.
• An established in vitro assay using human recombinant TPO (hrTPO) provides a tool to assess chemical impacts on TPO activity.

Purpose of the Study:

• To investigate the effects of various environmental chemicals on TPO activity.
• To evaluate benzophenones (BPs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) as potential thyroid disruptors.
• To establish TPO activity as a sensitive endpoint for detecting thyroid-disrupting chemicals.

Main Methods:

• Utilized an established in vitro assay employing human recombinant TPO (hrTPO) in FTC-238 cells.
• Exposed the TPO assay system to a range of chemicals including BPs, PAHs, and POPs.
• Compared the effects of tested chemicals against positive controls like methimazole (MMI) and genistein.

Main Results:

• Benzophenones, PAHs, and POPs showed slight alterations in TPO activity at low doses.
• Specific chemicals such as benzophenone, PFOS, and PFOA decreased TPO activity.
• Other chemicals, including 2,4-dihydroxy BP and dibenzo(a,h)anthracene, increased TPO activity.

Conclusions:

• Environmental chemicals can modulate thyroperoxidase activity, impacting thyroid hormone synthesis.
• TPO activity serves as a sensitive biomarker for predicting the thyroid-disrupting potential of chemicals.
• Regulatory measures for environmental exposure should consider the impact on TPO activity and the TH axis.