ABSTRACT
Calcitonin (CT) 2+ loss during Ca2+ reserves, and plasma concentrations of 1,25(OH)2D and CT are both elevated during pregnancy. Besides hypercalcemia, estrogens also enhance CT release, as do the gut hormones cholecystokinin (CCK), glucagon, and gastrin (Part E). Glucagon release from a necrotic pancreas may stimulate excessive CT release, thus leading to hypocalcemia. It appears that a high-Ca2+ diet releases gastrin, which in turn acts as an anticipatory hormone causing CT release. Gastrin also increases gastric HCl secretion, which releases dietary Ca2+ bound to protein (a prerequisite for absorption). Calcitonin, in turn, feeds back negatively on gastrin.
