07- Drugs for pituitary, thyroid and adrenal disorders Flashcards
What are the “master glands”?
Hypothalamus and the pituitary
Why kind of relationship does the posterior pituitary have with the hypothalamus?
A neuronal relationship
What do the hypothalamus and the pituitary do?
Regulate the function of numerous endocrine glands, control major physiological processes in the body
What does the hypothalamus do?
Secretes hormones that regulate the function of the anterior pituitary
Can GnRH or GH be used clinically?
Limited use clinically
In what way is it easier to deal with clinical issues?
Easier to deal with the root issue as opposed to the activity of the glands upstream
Where do pituitary disorders arise from?
- Tumors
- Injury
- Radiation therapy
- Infection
- Infarction
- Hemorrhage
- Congenital defects
What is growth hormone? What is it also known as?
Somatotropin, anterior pituitary hormone stimulating growth and metabolism, its important throughout the lifespan
What is antidiuretic hormone?
Hormone that acts on the kidneys to increase water re-absorption, released because of increased osmolality
Where is ADH stored?
Stored and released by the posterior pituitary
What kind of drug would we give if someone isn’t making enough growth hormone?
Growth hormone agonist
What kind of drug would we give if someone is making too much growth hormone?
Growth hormone antagonist
What does growth hormone (somatotropin) deficiency result in?
- Short stature in children
- Dyslipidemia
- Decreased muscle mass
- Central adiposity
- Decreased bone density
- Increased cardiovascular mortality
What is the greatest increase we would see with administration of somatropinin in the height of a child without fused bone plates?
15 cm
What is the difference between somatotropin and somatropin?
Somatotropin = endogenous ligand/hormone Somatropin = agonist drug
What does somatropin do?
- Increases height in patients with short stature (associated with genetic disease) and in adults as a replacement therapy
- Increases protein synthesis and lean muscle mass, bone density, lipid mobilization from fat stores, improved lipid profile
What happens when there is too much growth hormone?
Causes acromegaly
What physical appearance changes occur with hypersecretion of GH?
- Very tall
- Broad nose
- Broad forehead
- Large hands
- Bones get thicker and larger
- Enlarged heart, feet, tongue, lips
What symptoms occur with hypersecretion of GH?
- Headaches
- Visual disturbances
- Fatigue
- Excessive sweating
Why do patients with acromegaly experience headaches?
The bones become thicker, it causes increased intracranial pressure which leads to the bad headaches
What happens to patients with acromegaly when they are given a GH agonist?
Will only see changes in soft tissue but not in bone
What are the growth hormone antagonists?
- Octreotide
- Pegvisomant
What is octreotide?
- Pharmacologically related to somatostatin (growth hormone inhibiting hormone produced by the hypothalamus)
- Demonstrates a prolonged duration of action compared to GHIH
- Signals the pituitary to produce less GH, mild efficacy, blocks GH from receptor
What is pegvisomant?
- Growth hormone receptor antagonist acts at target tissues
- More effective than GHIH drugs
- Good at reversal of soft tissue damage, more efficient than octreotide
What does under-production of anti-diuretic hormone cause?
Diabetes insipidus
What occurs with decreased levels of ADH?
- Kidneys reabsorb fluid, this causes dilute urine
- Patient is very thirsty
What is ADH also known as?
Vasopressin, acts like ADH but is also a potent vasoconstrictor