The calcium-sensing receptor: a window into the physiology and pathophysiology of mineral ion metabolism

N Chattopadhyay, A Mithal, EM Brown - Endocrine Reviews, 1996 - academic.oup.com
N Chattopadhyay, A Mithal, EM Brown
Endocrine Reviews, 1996academic.oup.com
I. Introduction CALCIUM 1 (Ca2+) ions are of critical importance for a variety of vital bodily
functions (1–4). Intra-and extracellular Ca2+ act in distinct but sometimes complementary
ways to regulate a multitude of biological processes. The cytosolic free calcium
concentration ([Ca2+] i) plays a pivotal role in controlling cellular processes such as
secretion, differentiation, and motility (2, 5). Calcium ions act as key intracellular second
messengers and also as cofactors for a number of enzymes. Although [Ca2+ [i generally …
I. Introduction
CALCIUM 1(Ca2+) ions are of critical importance for a variety of vital bodily functions (1–4). Intra- and extracellular Ca2+ act in distinct but sometimes complementary ways to regulate a multitude of biological processes. The cytosolic free calcium concentration ([Ca2+]i) plays a pivotal role in controlling cellular processes such as secretion, differentiation, and motility (2, 5). Calcium ions act as key intracellular second messengers and also as cofactors for a number of enzymes. Although [Ca2+[i generally exists at much lower levels than the extracellular calcium concentration ([Ca2+[o), it can undergo large, rapid changes due to either influx through the cell membrane or release from intracellular stores (2,5). [Ca2+[o, on the other hand, remains remarkably constant, varying by only a few percentage points over much of a lifetime under normal circumstances (1, 3,4). [Ca2+[o likewise plays an essential role in numerous processes, including blood clotting, neuromuscular excitability, and maintenance of the integrity of the skeletal system.
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