GLOSSARY

Three organs in communication

Calcium and phosphate regulation coordinates intestine, kidney and bone through PTH, vitamin D-related signals and FGF23. Ionized calcium, renal function and tissue responsiveness influence the pattern. Serum concentration alone does not measure skeletal mineral stores.

Interpreting the mechanism

This metabolite is commonly used for status assessment and is distinct from active calcitriol.

Bone under load

Mechanical loading supplies local signals that interact with endocrine state, adequate energy and nutrient availability. A circulating bone marker can reflect several skeletal sites and does not independently prove stronger bone or predict fracture risk.