Chapter 7 – The Parathyroid Gland:: Regulation of Production of Parathyroid Hormone

Parathyroid hormone secreted from the parathyroid gland plays a significant role in maintaining Ca 2+ homeostasis. There are four levels of regulation in the production of PTH: transcription, secretion, intracellular degradation, and cellular proliferation, all of which determine the circulating level of PTH. The regulation of secretion and degradation is important to maintain homeostasis in response to the rapid change of [Ca 2+ ]e. Extracellular concentrations of calcium in the physiologic range regulate PTH production at all levels. Bodily adaptations in response to chronic changes in calcium levels occur at the level of transcription and cellular proliferation. Although there are several candidates for second messengers mediating the change of [Ca 2+ ]e at secretion level, no one candidate has been clearly identified to solely mediate inhibition of PTH secretion, and several pathways may act in concert.