Synonyms
Parathormone, Parathyrin
Description
PTH (parathyroid hormone) is a critical hormone in the regulation of Ca++ homeostasis. PTH is secreted by the chief cells of the parathyroid glands as a polypeptide. PTH secretion is enhanced by low Ca++ concentrations and inhibited by FGF-23. In normal human plasma, PTH correlates negatively with active Vitamin D and positively with ionized calcium. Human and other mammalian PTH will bind and stimulate human or rat PTH1R, activating adenylate cyclase and increasing cAMP production. PTH promotes secretion of TRANCE/RANKL and periostin through PTH1R binding on osteoblasts and/or bone marrow stromal cells TRANCE/RANKL induces differentiation of osteoclasts, which in turn promote release of Ca++ from bone. PTH1R on osteocytes, however, allows PTH to promote bone formation and IGF-1 production. In addition, PTH increases hematopoietic stem cell proliferation and mobilization and induces arterial vasodilation by regulating Ca++ influx in PTH1R-expressing arterial smooth muscle. In renal epithelium, PTH promotes conversion of Vitamin D to its active form, lowers Ca++ excretion and increases phosphate excretion.
Molecular Weight
Approximately 9.4 kDa.
AA sequence
SVSEIQLMHN LGKHLNSMER VEWLRKKLQD VHNFVALGAP LAPRDAGSQR PRKKEDNVLV ESHEKSLGEA DKADVNVLTK AKSQ
Appearance
Sterile Filtered White lyophilized (freeze-dried) powder.
Purity
> 97% by SDS-PAGE and HPLC analyses.
Biological Activity
The ED50 as determined by its ability to induce cAMP accumulation in murine MC3T3E1 cells is less than 50 ng/mL, corresponding to a specific activity of > 2.0×104 IU/mg. Fully biologically active when compared to standard.
Endotoxin
< 1.0 EU per 1μg of the protein by the LAL method.
Formulation
Lyophilized from a 0.2 µm filtered concentrated solution in PBS, pH 7.4.
Reconstitution
We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20°C. Further dilutions should be made in appropriate buffered solutions.