Parathyroid Hormone
Parathyroid Hormone (PTH, also known as PTH1) is a peptide hormone secreted by parathyroid chief cells. It acts as a primary endocrine regulator of extracellular calcium and phosphate homeostasis, working mainly on bone and kidney through the receptor PTH1R. Browse Assay Genie's current range of Parathyroid Hormone research reagents below, or read on for the biology behind the target.
Parathyroid hormone is secreted by parathyroid chief cells and keeps serum calcium within a narrow range, acting mainly on bone and kidney. It binds and activates the G protein-coupled receptor PTH1R, which engages G(s)-mediated cAMP/PKA signalling and G(q)-mediated PLC/PKC signalling.
In bone, PTH acts indirectly on osteoclasts. It binds PTH1R on cells of the osteoblast/osteocyte lineage, increasing expression of TNFSF11/RANKL and decreasing expression of TNFRSF11B/OPG. The higher RANKL/OPG ratio stimulates osteoclast differentiation and bone resorption. It also stimulates 2-deoxy-D-glucose transport and glycogen synthesis in osteoblastic cells. In the distal renal tubule, PTH stimulates active Ca(2+) reabsorption through the adenylyl cyclase-cAMP-PKA pathway, which phosphorylates and activates the calcium-selective channel TRPV5. In proximal tubule cells, PTH1R-activated PKC phosphorylates the scaffold NHERF1. This dissociates the NHERF1-SLC34A1 complex and leads to clathrin-mediated endocytosis and lysosomal degradation of the cotransporter, reducing phosphate reabsorption. PTH also drives transcription of CYP27B1 through a cAMP/PKA/SIK2-SIK3/CRTC2 axis, raising renal synthesis of 1,25-dihydroxyvitamin D(3).
The PTH gene belongs to the parathyroid hormone family and is classed by HGNC among receptor ligands. The encoded preproprotein is proteolytically processed to the active hormone, and alternative splicing gives multiple transcript variants. Excess production, known as hyperparathyroidism, can cause hypercalcaemia and kidney stones. Defective processing may lead to hypoparathyroidism, which can result in hypocalcaemia and numbness.
PTH is a primary endocrine regulator of extracellular calcium and phosphate, making it central to studies of mineral balance.
PTH raises the RANKL/OPG ratio through PTH1R on osteoblast/osteocyte lineage cells, stimulating osteoclast differentiation and bone resorption.
PTH regulates TRPV5-mediated calcium reabsorption, SLC34A1-dependent phosphate handling and CYP27B1-driven synthesis of active vitamin D.
Excess PTH production causes hyperparathyroidism, while defective processing may lead to hypoparathyroidism, so the hormone anchors work on these disorders.
PTH is secreted by parathyroid chief cells and maintains serum calcium within a narrow range. It activates PTH1R in bone and kidney, stimulating bone resorption, increasing renal calcium reabsorption, reducing phosphate reabsorption and promoting synthesis of active vitamin D.
PTH is also listed under the alias PTH1, and its full name is parathyroid hormone. The gene encodes a preproprotein that is proteolytically processed into the active hormone. Alternative splicing of the gene results in multiple transcript variants.
Mouse and rat both have a Pth ortholog; check the datasheet of any product for its validated reactivity. Excess PTH (hyperparathyroidism) can cause hypercalcaemia and kidney stones, while defective processing may lead to hypoparathyroidism and hypocalcaemia.
Receptors, bone-remodelling regulators and renal transport proteins that act alongside parathyroid hormone.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P01270; product specifications from Assay Genie datasheets.