Friday, March 5, 2010

Parathyroid Chief Cells

Also known as parathyroid principal cells, the parathyroid chief cells are cells in the parathyroid glands which secretes parathyroid hormone. They are often divided into dark chief cells and light chief cells. A parathyroid cell is a round and clear cell with a centrally located nucleus.

Parathyroid chief cells are one of the few cell types which regulate intracellular calcium levels as a consequence of extracellular changes in calcium concentration. The end result of increased secretion by the chief cells of a parathyroid gland is an increase in the serum level of Calcium. The calcium-sensing receptor is sensitive to an increase in serum calcium, and stimulates the uptake of calcium by the parathyroid chief cell. This mechanism is critically important, as it describes a physiological feed-back loop by which parathyroid hormone secretion is down-regulated in response to a restoration of serum calcium.