Parathyroid hormone: regulation of synthesis and secretion.

Calcium homeostasis is essential for survival and is primarily achieved through the actions of parathyroid hormone. Parathyroid hormone secretion and synthesis are primarily regulated by serum calcium levels, although other factors such as vitamin D and neurotransmitters play a role. This review is intended to provide the reader with up to date information on the current state of basic cell regulation research into parathyroid function. While some mention of disease states is made, the focus of this review is on the calcium regulation of parathyroid hormone secretion at the molecular level. Individual sections will discuss calcium-sensing, signal transduction by calcium and other secretagogues, regulation of parathyroid hormone synthesis, and strategies of regulation of parathyroid hormone secretion by calcium. Particular emphasis is given to the calcium-stimulated degradation of parathyroid hormone within the parathyroid as one of the major pathways by which circulating levels of bioactive hormone are controlled.