Skin: Vitamin D3 → Chloecalciferol, Ergocalciferol

Liver: 25-OH Vitamin D → Alfacalcidol

Kidney: 1, 25-OH Vitamin D → Calcitriol (1,25 VD)

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Calcitriol (1,25 VD) vs. PTH : Effect on PO4 and Ca

Ca (2+) → Net Increase with PTH (normal cases)

PO4 (3-) → Net decrease with PTH (normal cases)

Normal range

• ≥ 70 mmol/L for good bone health