pituitary / bone mineral homeostasis

Question 1

oxytocin

Answer 1

• similar to vasopressin (antidiuretic hormone)
  
  • secreted from nerve endings of paraventricular nuerons ending in the posterior pituitiary
  • also released from ovarie luteal cells, fetal membrane
• progesterone antagonizes effects
• stims uterin contraction / milk ejection
• given IV infusion
• drug choice for labor induction

contraindicated in:

• prematurity
• fetal distresss
• abnormal fetal positioning
• ccephalopelvic disproportion

Question 2

Atosiban

Answer 2

• oxytocin receptor antagonist (like progesterone)

Question 3

vasopressin

Desmopressin

Answer 3

• primary ADH
• synthesis similar to oxytocin
• acts on kidney to promoter water retention via V2 receptors
• used in treatment for diabetes insipidus, nocturnal enuresis
• desmopressin is administered IV,IM or intranasal

Question 4

bone mineral abdnormalities

Answer 4

• neuromuscualr excitability, weakness and tetany
• skeletal structurla support disturbances
• loss of hematopoietic capacity

Question 5

PTH

Answer 5

• inc Ca and dec PO4
  
  • promotes bone remodelling
  • excess PTH = bone resorption

Question 6

Vit D

Answer 6

• inc Ca and PO4
• promotes Ca, PO4 absorption in intestinal tract & kidney –> bone resorption
• supresses PTH production
• can use to treat osteoporosis
  
  • supress bone remodeling
  • improve mineral density

Question 7

Calcitonin

Answer 7

• lowers Ca and PO4
• inhibits osteoclast
• reduce Ca, PO4 reabsorption by kidney
• inhibits bone resorption by osteoclasts in some patients w/ osteoporosis

Question 8

Estrogens

Answer 8

• oppose PTH actions
• dec bone turnover
• inc Vit D levels

Question 9

Osteoporosis

Answer 9

• low bone mass from abnormal mineral loss –> inc fracture
• primary
  
  • commonly seen in postmenopausal women –> loss estrogen
• Risk factors
  
  • female caucasian
  • smoking
  • history of prior fracture
  • age
  • low body weight
  • familial history
• secondary
  
  • perimenopausally
  • postmenopausally
• Risk factors
  
  • Diet
  • Gi disease
  • hyperparathyroidism
  • liver disease
  • alcoholism
  • vit d deficiency

Question 10

Raloxifene

Answer 10

• Selective estrogen receptor modulator
• treat and prevent osteoporosis
• does not prevent hot flashes

Question 11

Bisphosphates

Answer 11

• most successful therapy for prevention of osteoporosis
• inhibit osteoclast and bone resorption
• do not inhibit mineralization

Question 12

PTH analogues

Answer 12

• recombinant PTH, daily SC injections
• stimulates bone formation than inhibit resorption
• to treat osetoporosis