Introduction Calcium homeostasis controlled by a combination of vitamin D and PTH PTH Pathway Synthesis secreted by the chief cells of parathyroid Function ↑ serum free Ca2+ and ↓ serum phosphate in response to hypocalcemia/hypomagnesemia via ↑ bone resorption of calcium and phosphate (bone is destroyed) PTH receptor is on the osteoblasts secretes IL-1 to activate osteoclasts via production of M-CSF and RANK-L PTH decreases osteoprotegrin (OPG), decoy receptor for RANKL, thereby resulting in an increased interaction between RANKL and osteoclasts ↑ kidney resorption of calcium in distal convoluted tubule ↓ kidney resorption of phosphate (increasing urine phosphate) ↑ 1,25-(OH)2 vitamin D production (via 1 alpha-hydroxylase) Clinical Conditions Hypoparathyroidism Hyperparathyroidism Familial hypocalciuric hypercalcemia defective calcium receptor that can not detect elevated calcium level loss of negative feedback causes hypercalcemia (via increased PTH, 1-alpha OH)
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All Videos (1) Login to View Community Videos Login to View Community Videos Endocrinology - Calcium and Phosphate Regulation Gio Sabal Endocrine - Parathyroid Hormone (PTH) D 8/24/2015 97 views 5.0 (4)