Avian Parathyroid Physiology: Including a Special Comment on Calcitonin

During the reproductive cycle, the females of avian species metabolize large amounts of calcium, deposit large amounts of apatite in intramedullary bone, and develop hyperplastic and hypertrophied parathyroid glands. Secondary hyperparathyroidism develops when the amount of calcium in the diet is low. Hyperparathyroidism, either endogenous or from injections of parathyroid extract, produces resorption of endosteal bone and not mobilization of...