Description
Calcium-sensing receptor (CaSR) is a G protein-coupled receptor that is involved in calcium homeostasis. Activation of CaSR on parathyroid cells decreases the secretion of parathyroid hormone (PTH), which in turn reduces blood calcium concentration. NPS 2143 is a potent and selective antagonist of CaSR (IC
50 = 43 nM) that stimulates PTH secretion from parathyroid cells
in vitro (EC
50 = 39 nM). It is effective
in vivo, causing a sustained increase in plasma PTH in rats when given intravenously. Daily oral administration of NPS 2143 to osteopenic ovariectomized rats results in a dramatic increase in bone turnover, as well as increased circulating PTH levels.
Biochem/physiol Actions
NPS2143 is a phenylalkylamine calcilytic compound, and might be useful in treating autosomal dominant hypocalcemia. It serves as a blocking agent for hERG (human ether-a-go-go-related gene ) channel, CYP2D6 (cytochrome P450 2D6 ) and monoamine transporters.