4 - Parathyroid Hormone and Ca Homeostasis

Question 1

Plasma calcium is regulated by? (3)

Answer 1

PTH

Vitamin D

Calcitonin

Question 2

PTH secretion is regulated by (1)

Answer 2

Plasma Ca levels

Question 3

PTH Actions: Bone (2)

Answer 3

Increases bone resorption by increasing the no. and activity of osteoclasts

Induce Receptor Activator Nuclear Factor Kappa-B Ligand (RANKL) –> increases both the numbers and the activity of osteoclasts

Question 4

PTH Actions: Kidney (2)

Answer 4

Increases the reabsorption of Ca and reduces that of phosphate

Stimualtes the production of 1,25-dihydoxyvitamin D

Question 5

PTH Actions: Intestines (1)

Answer 5

Indirectly increases absorption of Ca

Question 6

Teriparatide (Forteo): Defined and Use

Answer 6

Recombinant PTH

Used in osteoporosis in intermittent administration

Question 7

Calcitonin: Secreted and Regulated (2)

Answer 7

Secreted by parafollicular ‘C’ cells of thyroid

Regulated by plasma Ca levels

Question 8

Calcitonin Actions: Bone and Kidney

Answer 8

Bone: Inhibits osteoclastic bone resorption

Kidney: Inhibits reabsorption of Ca and PO4

Question 9

Calcitonin Use (3)

Answer 9

Paget’s Disease

Hypercalcemia

Osteoporosis

Question 10

Vitamin D3 is also called

Answer 10

Cholecalciferol

Question 11

Vitamin D2 is also called

Answer 11

Ergocalcierfol

Question 12

Vitamin D: Activation

Answer 12

Hydroxylated in the liver to 25-hydroxyvitamin D → 1,25-dihydroxyvitamin D (calcitriol)

Question 13

Vitamin D Actions: Intestine

Answer 13

Increases absorption of Ca and PO4

Question 14

Vitamin D Actions: Bone

Answer 14

Increases Ca and PO4 resorption

Question 15

Vitamin D Actions: Kidney

Answer 15

Excretion of Ca ad PO4 is decreased

Question 16

Vitamin D Uses (4)

Answer 16

Prophylaxis and treatment of Vitamin D deficiency

Rickets: Vit D resistant rickets and Vit D dependant rickets

Renal rickets

Hypoparathyroidism

Question 17

Biphosphonates: Drugs (4)

Answer 17

Etidronate

Pamidronate

Alendronate

Risendronate

Question 18

Biphosphonates: Mechanism (3)

Answer 18

Slow formation and dissolution oh hydroxyapatite crystals

Localize to regions of resorption

Block farnesyl pyrophosphate

Question 19

Biphosphonates: Uses (4)

Answer 19

Osteoporosis

Paget’s Disease

Hypercalcemia of malignancy

Osteoclastic Bone Metastatis

Question 20

Biphosphonates: Adverse Effects (4)

Answer 20

Decreased renal function

Esophageal motility disorders

Peptic ulcer disease

Osteonecrosis of the jaw (tx with Zolendronate)

Question 21

What drug inhibits RANKL and it’s use (2) ?

Answer 21

Denusomab (Prolia)

Osteoporosis and giant cell tumor of bone

Question 22

Cinacalcet: MOA (2)

Answer 22

Activates Calcium-sensing receptor parathyroid gland - calcimimetic

Blocks PTH secretion

Question 23

Cinacalcet: Use (2)

Answer 23

Secondary hyperparathyroidism in chronic kidney disease

Parathyroid carcinoma

Question 24

Plicamycin: MOA (1)

Answer 24

Cytotoxic antibiotic that inhibits bone resorption

Question 25

Plicamycin: Use (2)

Answer 25

Hypercalcemia Paget's Disease

Question 26

Gallium Nitrate is used in?

Answer 26

Hypercalcemia