Mother did not know how right she was in exhorting her children to drink milk. In addition to building strong bones and teeth, data have been accumulating that on an "ionic" level calcium regulates cell functions as diverse as insulin secretion, muscle contraction, and mast cell degranulation. In addition, calcium plays an important role in regulating proliferation and differentiation of the skin.
Nature maintains steep calcium gradients in and outside cells that allows calcium to act as an internal messenger, translating extracellular signals into cellular responses.1 Calcium is normally stored in the endoplasmic reticulum and mitochondria, and a low, free intracellular concentration in the cytoplasm is maintained (10-7 mol/L). However, the free intracellular calcium is the physiologically active internal calcium. Calcium levels outside the cells and in the storage compartments are 10000 times higher than the free intracellular calcium concentration. Transport of small amounts of calcium from the