TBG

TBG is an acronym used in multiple fields to denote different terms, with no single universally definitive meaning. The most widely recognized use in biology and medicine is thyroxine-binding globulin (TBG), a liver-produced plasma glycoprotein that binds thyroid hormones, mainly thyroxine (T4) and, to a lesser extent, triiodothyronine (T3). By binding these hormones, TBG helps regulate their circulating availability and helps maintain hormonal balance. TBG levels can be influenced by physiological and pathological conditions, including pregnancy, estrogen therapy, liver disease, and certain genetic variants. Because total thyroid hormone measurements depend on TBG levels, clinicians may interpret results with consideration of TBG status, while free hormone assays provide complementary information.

In biotechnology and genetics, TBG can refer to the thyroxine-binding globulin promoter, a regulatory DNA element used in some mammalian expression systems to drive liver-specific gene expression. This promoter is employed in research and therapeutic contexts to achieve targeted expression in hepatocytes.

Beyond biology, TBG is used as an initialism for various organizations, companies, and groups, with different full names depending on the country and sector. Because the same acronym appears across diverse domains, its precise meaning is determined by context, including field, geography, and accompanying terms.