Only ionized calcium has a regulatory role
Affected by
- Calcitonin (small effect)
- PTH-Vitamin D axis
<aside>
Calcitriol (1,25 VD) vs. PTH : Effect on PO4 and Ca
Ca (2+) → Net Increase with PTH (normal cases)
| Molecule | PTH | Calcitriol (1,25 VD) |
|---|---|---|
| Kidney | ↑ Ca re-absorption | ↑ Ca |
| Intestine | NA | ↑ Ca absorption |
| Bone | ↑ Osteoclast, ↑ Ca | ↑ Osteoclast, ↑ Ca |
PO4 (3-) → Net decrease with PTH (normal cases)
| Molecule | PTH | Calcitriol (1,25 VD) |
|---|---|---|
| Kidney | ↓ PO4 (PTH dominant) | ↑ PO4 |
| Intestine | NA | ↑ PO4 absorption |
| Bone | ↑ Osteoclast, ↑ PO4 | ↑ Osteoclast, ↑ PO4 |
| </aside> |