calium homeostasis and bone metabolism

Question 1

calcium

Answer 1

in many signaling cascades, closely watched
watched with phosphate regulation; increase in phosphate > increase in Ca2+ phosphate > decrease in Ca2+ concentration

the more free Ca2+ in blood, the less PTH. Ca2+ binding to CaSR blocks the PTH gene

Question 2

calcitriol

Answer 2

promotes Ca2+ uptake in the intestine
vitamin D is converted into calcitriol

• negative feedback on PTH
• activates OCs, cell differentiation

Question 3

calcitonin

Answer 3

thyroid gland produced
reduces Ca2+ concentration through;
- inhibition of Ca2+ and phosphate resorption in the kidney
- promotion of Ca2+ deposition in bone through suppression of OCs

Question 4

PTH

Answer 4

produced by parathyroid
effects;
- absorption of Ca2+ and phosphate from bone; OC
- increase in Ca2+ reabsorption and reduced phosphate reabsorption in the kidney
- facilitation of Ca2+ uptake in the intestine, by calcitroil

Question 5

oestrogens

Answer 5

suppression of OC differentiation
promotion of OB proliferation

raloxifene
SERM

Question 6

glucocorticosteroids

Answer 6

stimulation of OC
inhibition of OB

Question 7

bisphosphonates

Answer 7

prevent attachment of OC, apoptosis

Question 8

denosumab

Answer 8

anti-RANKL

Question 9

teriparatide

Answer 9

increase bone formation
increase OBs

Question 10

strontium ranelate

Answer 10

decrease bone breakdown
decrease OC differentation

increased risk of myocardial infarction

Question 11

cinacalcet

Answer 11

allosteric calcium agonist
stimulates CaSR, inhibiting the PTH