Glycoprotein hormone subunit beta 5 (GPHB5)

Glycoprotein hormone subunit beta 5 (GPHB5) is a cystine knot-forming polypeptide and a member of the glycoprotein hormone beta subunit family[3][5][7]. In humans, GPHB5 forms a non-covalent heterodimer with glycoprotein hormone alpha 2 (GPHA2), creating the hormone thyrostimulin[2]. This heterodimer acts as a ligand for the thyroid-stimulating hormone receptor (TSHR), activating it and promoting cAMP production and thyroid hormone synthesis[2][5]. GPHB5 is expressed in several tissues, including pituitary, brain, testis, skin, heart, and liver[1]. Recent studies suggest that circulating levels of GPHB5 are elevated in individuals with metabolic syndrome and obesity, making it a potential biomarker for these conditions[1]. GPHB5 is not known to be regulated acutely by glucose or insulin in humans, though preclinical data indicate it affects energy metabolism and may contribute to metabolic and thyroid disorders[1][2]. No approved drugs currently target GPHB5 directly, but GLP-1 receptor agonists have been shown to reduce circulating GPHB5 levels[1].

Other names

Glycoprotein hormone beta-5GPB5Thyrostimulin subunit betaZLUT1OGHB5Glycoprotein hormone subunit β 5Glycoprotein hormone β 5Thyrostimulin beta-5 subunit

GPHB5 acts as a ligand for the thyroid-stimulating hormone receptor (TSHR). It heterodimerizes with GPHA2 to form thyrostimulin, which activates TSHR, stimulating cAMP production. This mechanism modulates thyroid hormone synthesis and secretion.