Explanation

Parathyroid Hormone (PTH) increases the $Ca^{2 +}$ in the blood. PTH acts on bones and stimulates the process of bone resorption (dissolution/demineralisation). PTH also stimulates the reabsorption of $Ca^{2 +}$ by the renal tubules and increases $Ca^{2 +}$ absorption from the digested food. It is thus clear that PTH is hypercalcemic hormone, i.e., it increases the blood $Ca^{2 +}$ level. Along with TCT, it plays a significant role in calcium balance in the body