Parathyroid hormones (PTH) increases the Ca++ concentration and slightly decreases phosphate ion concentration in the blood.
When Parathyroid hormone increases, the body release more calcium from bones into blood which lead to the increase in calcium concentration in the blood.
The parathyroid hormone increase in the other hand led to slightl
y decrease in phosphate ions since it reduces the reabsorption of phosphate from proximal tubule of the kidney