<prompt> Parathormone Parathyroid hormonePTH increase calcium levels and reduces phosphate level by acting onProximal tubulesDistal tubulesThick ascending limb of Loop of HenleAll of the above  <response>: The kidney excretes 250 mmol a day in pro-urine, and resorbs 245 mmol, leading to a net loss in the urine of 5 mmold. In addition to this, the kidney processes Vitamin D into calcitriol, the active form that is most effective in assisting intestinal absorption. Both processes are stimulated by parathyroid hormone.Ref: Ganong;s review of medical physiology; 24th edition; page no:-377 