Calcium and Bone Metabolism: Parathyroid Disorders, Vitamin D Biology, and Metabolic Bone Disease

This chapter provides a detailed review of the endocrine regulation of calcium-phosphate homeostasis, including recent advances in parathyroid hormone (PTH) and PTH-related peptide biology, fibroblast growth factor-23 (FGF-23) signaling, and vitamin D metabolism at the molecular level. Disorders including primary hyperparathyroidism, hypoparathyroidism, osteoporosis, and rare metabolic bone diseases are examined through the lens of contemporary pathophysiology. Therapeutic innovations — including anabolic bone agents, receptor activator ligands, and calcimimetics — are comprehensively reviewed.