PTH and Hypocalcemia: As shown in previous studies, the secretion of PTH(1–84) and PTH(7–84) from parathyroid cells are regulated differently: PTH(1–84) is secreted more under conditions of hypocalcemia, and PTH(7–84) is secreted more under conditions of hypercalcemia.25, 26, 27 Because evocalcet decreases serum calcium levels, it may affect the levels of whole and intact PTH differently.