NPS-2143 hydrochloride (SB-262470A hydrochloride), an orally active calcilytic agent, is a selective and potent calcium ion-sensing receptor (CaSR) antagonist. NPS-2143 hydrochloride (SB-262470A hydrochloride) blocks increases in cytoplasmic Ca2+ concentrations (IC50=43 nM) elicited by activating the Ca2+ receptor in HEK 293 cells expressing the human Ca2+ receptor[1][2].
NPS-2143 hydrochloride (SB-262470A hydrochloride) stimulates parathyroid hormone (PTH) secretion from bovine parathyroid cells with EC50 of 41 nM. Moreover, NPS-2143 hydrochloride also blocks the inhibitory effects of calcimimetic NPS R-467 on PTH secretion from bovine parathyroid cells and the inhibitory effects of extracellular Ca2+ on isoproterenol-stimulated increases in cyclic AMP formation[1].
When infused intravenously in normal rats, NPS-2143 hydrochloride (SB-262470A hydrochloride) causes a rapid and large increase in plasma levels of PTH. Ca2+ receptor antagonists are termed calcilytics and NPS-2143 is the first substance (either atomic or molecular) shown to possess such activity[1].When administered together with an antiresorptive agent (estradiol), NPS 2143 causes an increase in trabecular bone volume and bone mineral density in osteopenic rats[2].
References:
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