Parathyroid hormone increases the blood concentration of this hormone, while calcitonin reduces it.
A common helix-loop-helix binding region that binds this element to various proteins is known as an EF hand.  This element often forms pentagonal bipyramidal coordination structure when bound to oxygen.  This element is involved in the fast-block to polyspermy, and the intracellular concentration of this element increases within the egg upon fertilization. Rhyanodine receptors allow the (*) ER to release stored concentrations of this element, which binds to troponin in order to expose the tropoymosin complex and allow muscle contraction. Parathyroid hormone increases the blood concentration of this hormone, while calcitonin reduces it. FTP, name this element that is used by osteoblasts to form bones.
A common helix-loop-helix binding region that binds this element to various proteins is known as an EF hand.  
{calcium} ({also} accept {Ca})