Hypothalamic & pituitary hormones

Question 1

Somatotropin

Answer 1

• MOA
• recombinant form of human GH
• acts through GH receptors to increase production of IGF-I
• Effects
• restores normal growth and metabolic GH effects in GH-deficient individuals
• Clinical
• replacement in GH deficiency
• wasting in HIV infection
• short bowel syndrome
• Kinetics, tox, int.
• SC injection
• tox: pseudotumor cerebri, slipped capital femoral epiphysis, edema, hyperglycemia, upper airway obstruction or sleep apnea

Question 2

Octreotide

Answer 2

• MOA
• agonist at somatostatin receptors
• Effects
• inhibits production of GH and, to a lesser extent, of TSH, glucagon, insulin, and gastrin
• Clinical
• acromegaly, horrmone-secreting tumors
• acute control of bleeding from esophageal varices
• Kinetics, tox, int.
• SC or IV injection
• long-acting formulation injected IM monthly
• tox: GI disturbances, gallstones, bradycardia, cardiac conduction problems

Question 3

Oxytocin & atosiban

Answer 3

• Oxytocin
• activates oxytocin receptors
• causes increased uterine contractions
• induction and augmentation of labor, control of uterine hemorrhage after delivery
• IV or IM
• tox: fetal distress, placental abruption, uterine rupture, fluid retention, hypotension
• Atosiban
• oxytocin receptor antagonist
• decreased uterine contractions
• tocolysis for preterm labor
• IV
• tox: concern about increased rates of infant death

Question 4

Desmopressin

Answer 4

• MOA
• vasopressin receptor agonist
• relatively selective for V₂ receptor
• Effects
• acts in kidney collecting duct to decrease excretion of water
• acts on extrarenal V₂ receptors to increase factor VIII and vW-factor
• Clinical
• pituitary diabetes insipidus
• pediatric primary nocturnal enuresis
• hemophilia A and vW-disease
• Kinetics, tox, int.
• oral, IV, SC, intranasal
• tox: GI disturbances, headache, hyponatremia

Question 5

Conivaptan

Answer 5

• MOA
• antagonist of vasopressin V_1a and V₂ receptors
• Effects
• reduced renal excretion of water in conditions associated with increased vasopressin
• Clinical
• hyponatremia
• Kinetics, tox, int.
• IV