Parathyroid Hormone
"calcitonin puts the bone in, parathyroid get the bone out" ... when bone
'comes out', both calcium and phosphorus are released..., but kidney action
lowers removes phos
- Released in response to Low serum Calcium
- Needs Magnesium in order to be released appropriately
Bone:
- Break down bone to release
Calcium and Phosphorous
Kidney:
- Help convert Calcidiol (25-hydroxy-Vitamin D or 25-hydroxycholecalciferol) into Calcitriol (active Vit D,
1,25-dihydroxycholecalciferol or 1,25-dihydroxy-vitamin D)
- Promotes phosphorous excretion in the kidneys
Vitamin D
- more accurately known as vitamin D3 or cholecalciferol
- in the liver, Vit D3 converted into calcidiol.
- Absorb Calcium and Phosphorous from the gut
Calcitonin
- Secreted primarily by the thyroid gland in response to high serum calcium
- Inhibits bone resorption/breakdown (decreases osteoclasts) and augments skeletal growth
- Is of little consequence in children and adults
- Mostly plays a role in the fetus
- Causes decreased osteoclasts, therefore used to treat Paget disease