Hormones affecting calcium metabolism Flashcards
what is the mechanism of action of the parathyroid hormone?
increase plasma Ca
decrease plasma PO4 by increasing formation fo active 1,23 - vit D3
increase bone resorption of Ca
increase kidney resorption of Ca
increase kidney excretion of phosphate
why would you want to give someone PTH?
what is the drug that stimulates PTH release?
for treatment of Osteoporosis
Teriparatide
what is the equivalent of 1,25 dihydroxyvitamin D3?
calcitriol
what is the net effect of Vit. D?
when do you want to amdminister Vit. D?
increase Ca and PO4 absorption in intestine
when you have hypocalcemia like in Rickets or hypoparathyroidism or renal disease or osteoporosis
what does Calcitonin do?
opposite effect of PTH
decreases Ca and PO4
- decrease bone resorption by inhibiting osteoclasts
- inhibits Ca and PO4 reabsorption in kidney
when do you use Calcitonin?
in hypercalcemia
what do you use for postmenopausal osteoporosis?
why?
estrogens
because they inhibit bone resorption by PTH
what do you use to reverse hypercalcemia in lymphoma and sarcoidosis?
why?
using glucocorticoids
because they antagonize intestinal Vit. D Ca absorption
what happens if you have glucocorticoid toxicity in adults?
what happens if you have glucocorticoid toxicity in children?
too much glucocorticoid causes osteoporosis in adults
too much glucocorticoid causes slow growth in children
why do you use Thiazide Diuretics?
how does that work?
hypercalcinuria
Increased Ca resorption from renal tubules
what drug do you use in Paget’s Disease?
how does the drug for the previous question work?
Plicamycin
reduce Ca levels and bone resorption
what happens if you have toxic levels of Biphosphonates?
gastric irritation and esophageal ulceration
when do you use biphosphonates and how do they work?
postmenopausal osteoporosis
- inhibits resorption of osteoclasts
biphosphonates all end in what?
what are the biphosphonates?
-dronates
- etidronate
- alendronate
- pmidronate
- residronate
- zolendronate
what causes hypercalcemia?
hyperparathyroidism
hypervitaminosis
sarcoidosis
