Connexin 43 is a protein found in human thyroid cells that helps cells communicate with each other. It is present in both healthy thyroid tissue and tissue affected by autoimmune disease, suggesting its presence is not dependent on disease state.

In human thyroid tissue, scientists can detect Connexin 43 at both the protein and genetic message levels, indicating that this protein is present and likely involved in how thyroid cells communicate with each other, as previously observed in animal studies.

In autoimmune thyroid disease, changes in the levels of a protein called connexin 43 are linked to differences in how well the thyroid gland produces and releases hormones.

In people with Graves' disease, a protein called Connexin 43 is found at higher levels in the thyroid, while in Hashimoto's thyroiditis, it is found at lower levels, compared to healthy thyroid tissue. This difference in protein levels is linked to whether the thyroid is overactive or underactive.

In two common autoimmune thyroid diseases, Graves' disease and Hashimoto's thyroiditis, the levels of a protein called connexin 43 differ in opposite directions, suggesting that how thyroid cells communicate with each other may be fundamentally different in these conditions.