Thyrotropin-releasing hormone receptor (TRHR) is a G protein-coupled receptor which binds thyrotropin-releasing hormone. The TRHR is found on the cell membrane of thyrotropes of the anterior pituitary. When the TRHR binds TRH it activates phospholipase C, which causes the formation of inositol triphosphate (IP3) and diacylglycerol (DAG). This leads to an increase in cytoplasmic calcium ion concentrations which stimulates the exocytosis of thyroid-stimulating hormone (TSH) into the blood. References Further reading External links G protein-coupled receptors