Vitamin D Flashcards
Vitamin D deficiency in young animals is called
Rickets
Vitamin D deficiency in adult animals is called
Osteomalacia
List 3 things vitamin D is important for
- Bone and teeth formation
- Intestinal absorption of calcium and phosphorus
- Renal reabsorption of calcium and phosphorus
1,25-dihydroxycholecalciferol’s primary function is to:
Increase calcium absorption from the intestine
Cholecalciferol (D3) is a vitamin D precursor of ______ origin
Animal
Ergocalciferol (D2) is a vitamin D precursor from ______ and ______
Fungi and plants
______ is the active form of vitamin D
Calcitriol
In the skin, 7-dehydrocholesterol is converted by sunlight into _______
Vitamin D3 (cholecalciferol)
D3 (cholcalciferol) is converted into 25-hydroxycholecalciferol by ________ in the liver.
25-hydroxylase
25-hydroxycholecalciferol is converted into 1,25-dihydroxycholecalciferol via _______ in the kidneys.
1-alpha-hydroxylase
Vitamin D3 is also called _________
Cholecalciferol
1,25-dihydroxcycholecalciferol is also called ______
Calcitriol
25-hydroxycholecalciferol is also called ________
Calcidiol
1 alpha-hydroxylase is a ______ enzyme in the kidney
Regulated
25-hydroxylase is a _______ enzyme in the liver
Non-regulated
PTH increases the synthesis of 1-alpha-hydroxylase. True or false?
TRUE
Phosphorus, calcium, calcitriol, and FGF-23 provide negative feedback on the action of 1-alpha-hydroxylase. True or false?
TRUE
25-hydroxycholecalciferol is converted into calcitriol via _________
1-alpha-hydroxylase
Vitamin D inhibits ________ proliferation and _______ secretion
Chief cell proliferation and PTH
Vitamin D increases absorption and reabsorption of _______ and _________
Calcium and phosphorus
Vitamin D facilitates ________ resorption
Bone
Vitamin D increases secretion of __________ from bone
FGF-23
Vitamin D analogs can be used to treat hyperparathyroidism in small animals and people in order to __________________
Suppress parathyroid cell proliferation and PTH synthesis
Vitamin D is has functions in immunomodulation and suppression of cell proliferation. True or false?
TRUE
Why do animals with CKD have increased PTH concentrations?
Bum kidneys = decreased activation of Vitamin D
Vitamin D inhibits PTH; less vitamin D = less inhibition of PTH
FGF-23 promotes excretion of ________
Phosphorus
FGF-23 inhibits activation of __________
Vitamin D
The active form of vitamin D (calcitriol) is produced in the ________
Kidneys
PTHrp is important for cell ___________ and _________
Proliferation and differentiation
