Bone Mineral Homeostasis-DONE Flashcards
Bone is a dynamic reservoir and there is constant remodeling, exchanging minerals with ___ and homeostasis is disrupted by ___ dysfunction?
intracellular fluid
intestine and kidney
What 2 minerals are important in bone homeostasis?
Calcium and phosphate
What are the principal hormone regulators of bone?
PTH
Fibroblast growth factor 23
Vitamin D
___ stimulates 1, 25 (OH2) D production in the kidneys
PTH
1,25 (OH2) D and Calcium _____ the production of PTH
suppress
1,25 (OH2) D stimulates intestinal absorption of ___
Calcium and phosphate
1, 25 (OH2) D and ___ stimulate proliferation and differentiation of osteoblasts and osteoclasts
PTH
PTH and 1,25 (OH2) D enhance ___ retention of calcium
renal
___ Promotes renal phosphate excretion
PTH
___ promotes renal absorption of phosphate
1,25 (OH2) D
___ stimulates renal phosphate excretion and inhibits renal production of 1, 25 (OH2) D
FGF23
1,25 (OH2) D and phosphate stimulate the production of ____
FGF23
Effects of PTH
Raises calcium and reduces phosphate
Effects of FGF23
decreases phosphate
Effects of Vitamin D
raises calcium and raises phosphate
What is a recombinant PTH 1-34 that in excess endogenous PTH Increases bone resorption? Low intermittent doses of PTH increase bone formation without stimulating bone resorption
Teriparatide
What are the reabsorption affects of PTH in the kidneys?
Increases Ca and Mg
Reduces Phosphate, Amino Acids, bicarbonate, Sodium, Chloride and Sulfate
T/F Women and men with osteoporosis at high risk of fractures.
TRUE
Teriparatide is at least as effective as bisphosphonates in preventing fractures
What are two cautions associated with Teriparatide (Forteo)
Watch for high calcium levels
Only use for 2 years ( + 2 years = osteosarcoma)
What are the 2 types of Vitamin D?
Cholecalciferol (natural form)
Ergocalciferol (plant based form)
What is the active metabolite of vitamin D?
1, 25 dihydroxyvitamin D or Calcitriol (Rocaltrol)
Where is vitamin D cleared and where is it stored?
Cleared by the liver
Stored in adipose tissue
Name 3 Vitamin D Analogs
Calcipotriene (Calcipotriol)
Doxercalciferol (Hectorol)
Paricalcitol (Zemplar)
Read the functions of Vitamin D Metabolites/Analogs
Intestinal calcium absorption Bone Resorption Renal Calcium and Phosphate reabsorption Decrease PTH Promote innate immunity Inhibit adaptive immunity
When do you use Vitamin D metabolites?
Osteoporosis Osteomalacia Renal failure Malabsorption Psoriasis
What is the MOA of calcitonin?
it lowers serum calcium and phosphate, inhibits osteoclastic bone resorption, and in time, reduces bone formation and absorption
What conditions is calcitonin useful in treating?
- Paget’s dz
- hypercalcemia
- osteoporosis