Parathyroid hormone (PTH) increases Ca2+ levels in the blood (hypercalcemic hormone) . It acts on bones and stimulates the process of bone resorption (dissolution/demineralisation) . It also stimulates the reabsorption of Ca2+ by the renal tubules and increases Ca2+ absorption from digested food . Therefore, decreasing Ca2+ levels (b), decreasing absorption from food (d), and regulating carbohydrate metabolism (e) are NOT effects of PTH. Carbohydrate metabolism is regulated by thyroid hormones and glucocorticoids .