Endocrine Flashcards
The adrenal medulla is responsible for secreting ____ and ____.
Epinephrine and Norepinephrine
The adrenal cortex secretes ______ and _____.
Corticosteroids and androgens
What effect does cortisol have on glucose levels?
Increases glucose levels
What are the cardiovascular effects of cortisol?
Increased CO and vasoconstriction
What is the effect that cortisol has on the fetus?
Induced fetal lung surfactant secretion
What are some of the physical findings of excess cortisol?
Buffalo hump, muscle wasting, moon face, striae, poor wound healing
What are some of the physical findings of too little cortisol?
Bronze pigmentation of the skin, changes in body hair distribution, GI disturbances, weakness, weight loss
What type of receptor is activated via glucticocorticoids?
intracellular nuclear transcription factor receptors
What is the response of glucocorticoid receptor activation?
Up or down regulation of specific genes
How is the metabolism of glucocorticoids slowed down?
Increasing oral effectiveness, increase the potency, increase the duration of action
What drug is used in endocrine replacement therapy?
Hydrocortisone
What receptors does hydrocortisone active?
GC and MC
What is the duration of hydrocortisone?
8-12 hrs (short acting)
How is prednisone different than hydrocortisone?
Intermediate acting (18-36 hrs), partially GC selective, slower metabolism
Which glucocorticoid is the longest acting?
Dexamethasone
Which GC drug is MC selective?
Fludrocortisone
What properties make dexamethasone long acting (36-54 hrs)?
Low protein binding (higher free drug concentration); slower metabolism
When would fludrocortisone be used?
adrenal failure, 21-hydroxylase deficiency
Which drug is a MC antagonist?
Spironolactone
What is the MOA for decreasing redness and swelling of GC?
Vasoconstriction, decrease vascular permeability, decrease histamine release
What is the MOA of how GC decrease fever and pain?
Inhibition of arachidonic acid metabolism which decreases prostaglandins and leukotrienes
What is the cause of the poor wound healing of excess GCs?
Decreased fibrin and collagen formation
Why is risk of infection a side effect of GC use?
suppression of the immune system via decreased leukocytes and inhibition of the neutrophils
Describe the proper ways to dose GCs?
Short term –> high dose or Long term–> low dose
Describe the feedback regulation effects of GC?
Suppression of the HPA axis which suppresses ACTH release
How are the GCs excreted?
Via the kidney
Side effects of MC receptor activation?
Hypernatremia, hypokalemia, edema, hypertension
What is the rate limiting step in TH synthesis?
The conversion of iodide to iodine via perioxidase
Long duration of action of levothyroxine (T4) is due to which factor?
highly protein bound
Slow onset of levothyroxine is due to what?
Conversion to T3 in the body
Why is liothyroine rapid onset?
less protein-bound and more potent
When should liothyroine be considered?
prior and following radioiodine treatment, TSH suppression
Why is there a slow onset with thyroid drugs?
it takes time to empty the plasma binding sites since the effects are mediated by protein synthesis and resetting metabolism
What drug interactions are present with thyroid drugs?
degradation of vitamin K dependent clotting factors (interfere with warfarin); Increase cardiac responsiveness to catecholamines