Correction of hyperphosphatemia normalized PTH in many early uremic cats,144 but was successful in only a portion of uremic dogs, many of which required calcitriol to normalize PTH.159 Step 2 is to administer intestinal phosphate binders in food (salts of aluminum, lanthanum or sevelamer, or calcium in hypocalcemic patients) to achieve a specific targeted serum phosphorus or PTH. This evidence concerns the gene PTH and hyperphosphatemia.