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Pharmacology · Chapter 6

Calcium, Vitamin D & the Bone Axis

Bone is not scaffolding — it is a calcium bank that is torn down and rebuilt every day, and the body will rob it without hesitation to keep the serum calcium in range. Every drug in this section does one thing at one address on that loop: the gland that senses calcium, the gut that absorbs it, the kidney that activates vitamin D, the cell that breaks bone down, or the cell that builds it back. Tap a site, then tap a drug to light up its target.

The calcium loop

Serum calcium
Bone mass
Six addresses on one looptap a site to begin
One loop, six answersSerum calcium is defended, not managed — and only a few places exist to interfere. A drug can change the PTH signal, the calcium that comes in from the gut, the vitamin D the kidney activates, the calcium the kidney keeps or dumps, the osteoclast that dissolves bone, or the osteoblast that rebuilds it. Pick a site to see its machinery.