Extrathyroidal T4 synthesis

Nagao and colleagues have developed a reliable tool for the measurement of serum thyroxine (T4), triiodothyronine (T3) and reverse T3 (rT3). Using this online solid-phase extraction liquid chromatography-mass spectrometry/mass spectrometry method, they found that levels of serum T4, T3 and rT3 in thyroidectomised rats were decreased but not completely ablated, suggesting an extrathyroidal supply of T4. Further, they found a decreased turnover rate of T4 in thyroidectomised rats, indicating that thyroidectomy suppresses the degradation of serum T4, thus maintaining T4 at a low level in a hypothyroid state. Nagao et al. (2011) Journal of Endocrinology 210 125–131.

Read the full article at: DOI:10.1530/JOE-10-0484.

For a commentary on this paper, see Ludgate (2011).