Intestinal calcium absorption: calcium entry.

Any consideration of calcium entry into the cell must recognize that it is the initial event in a complex sequentially integrated process. Any step in this process, when viewed individually and in isolation, may appear to be of overwhelming importance, but this need not be an accurate reflection of its relative role in the overall process. Calcium entry may be of substantial importance in terms of calcium transport rate or capacity under certain circumstances, but it is most likely not the sole limiting step in calcium absorption. The Symposium papers that follow stress the importance of additional factors and events that have been implicated in intestinal calcium absorption.