Effect of parathyroidectomy on plasma calcium levels in the seal salamander, Desmognathus monticola.

The parathyroid glands of Desmognathus monticola are located in the subdermal connective tissue of the neck. Although they are smaller than previously described urodele parathyroid glands, their histological structure is similar. Parathyroidectomy caused a decrease in plasma calcium concentrations within 4 days following the operation. By Days 12 and 21, however, the plasma calcium levels of parathyroidectomized animals were not significantly different from those of sham-operated animals. Thus, the parathyroid gland of this species contains a hypercalcemic principle, but the recovery from hypocalcemia suggests that some hypercalcemic mechanism other than the parathyroid system must be involved in calcium homeostasis.