The thyroid gland is comprised of thyroid follicles, in which thyrocytes surround a follicular lumen with the apical surface of a thyrocyte facing the lumen while the basal surface faces a basket-like capillary network evenly surrounding each thyroid follicle. Thyroglobulin (Tg), which is well known as the macromolecular precursor of thyroid hormone, is the most important and abundant protein produced and stored in thyroid follicles. Tg has been proposed, but not proven, to be this endogenous thyroid functional regulator.
Gerber et al. discussed the possibility that Tg within the colloid might be a factor determining the viscosity of the colloid and thereby creating different diffusion velocities of iodinated Tg and thyroid hormones. Using an in situ hybridization study of the thyroid-specific transcription factor Nkx2-1 in rats, researchers have directly implicated follicular Tg as a…
