Systemic calcium homeostasis

Systemic calcium homeostasis is the complex physiological process by which the body maintains extracellular calcium concentrations within a very narrow range, typically 8.5 to 10.5 mg/dL in humans (StatPearls, 2023). This regulation is vital for skeletal structural integrity, nerve impulse transmission, and muscle contraction. The system is governed by a multi-organ feedback loop involving the parathyroid glands, kidneys, bone, and intestines, primarily regulated by parathyroid hormone (PTH), calcitriol (active vitamin D), and the calcium-sensing receptor (CaSR) (NIH, 2022). When serum calcium levels drop, the CaSR triggers the release of PTH, which increases bone resorption and renal calcium reabsorption while stimulating the production of calcitriol to enhance intestinal absorption (PubMed, 2021). Dysregulation of this system leads to significant clinical pathologies, including osteoporosis, hyperparathyroidism, and chronic kidney disease-mineral and bone disorder (CKD-MBD). While 'systemic calcium homeostasis' is a physiological state rather than a single molecular target, various components of this pathway are targeted by drugs like calcimimetics, bisphosphonates, and PTH analogs to restore mineral balance (Journal of Clinical Investigation, 2013).

Other names

Calcium metabolismCalcium balanceMineral homeostasisCalcium regulation

Pharmacological agents modulate systemic calcium by targeting specific molecular components: calcimimetics allosterically activate the calcium-sensing receptor (CaSR) to inhibit PTH secretion; PTH analogs stimulate PTH receptors to increase bone turnover and renal calcium reabsorption; bisphosphonates and RANKL inhibitors reduce bone resorption by osteoclasts; and vitamin D analogs increase intestinal calcium absorption.