Adrenal Cortex Flashcards
The effects of cortisol are described as ______ which means
“permissive”
doesn’t directly initiate actions but allows critical processes to occur
amplies actions of other hormones
Only ______ cortisol is biological active
free
The net effects of cortisol are [catabolic/anabolic]
catabolic
How does cortisol affect energy metabolism?
increases blood glucose
increase glycogenesis
increase lipolysis and protein catabolism
increases, visceral obesity
How does cortisol increase blood glucose?
increase gluconeogenesis
increase glucagon release from pancreas to allow glycogenolysis
temporarily causing insulin resistance in tissues (muscles and adipose)
What tissues are insulin sensitive?
muscle
adipose
What do you do to cause insulin resistance?
decrease translocation of glucose transporters in cell membrane
How does cortisol increase glycogenesis?
blood glucose increases, eventually insulin:glucagon ratio increases
Glycogenesis starts in the _____
liver
Increasing lipolysis and protein catabolism provides _____
amino acids for gluconeogenesis
How does cortisol affect the musculoskeletal system?
increase protein catabolism
bone - inhibits bone formation, increases bone resorption, causes osteoporosis
connective tissue - inhibits collagen synthesis, causes thin skin
What are the effects of cortisol specifically on bone?
Inhibits bone formation
increases bone resorption
causes osteoporosis
Cortisol inhibits ____ absorption from small intestine
calcium
How does cortisol affect the kidneys and cardiovascular system?
increase glomerular filtration rate in kidney
decreases ADH (not reabsorb as much water)
helps maintain normal blood pressure and volume
unregulated alpha-1 adrenergic receptors
Cortisol upregulates what? It’s necessary for…
alpha-1 adrenergic receptors
necessary for vasoconstrictive response of arterioles to NE and Epi
How does cortisol affect the immune system?
suppresses immune response
suppresses prostaglandins, thromboxane, leukotrienes
specific anti-inflammatory effects
What are the specific anti-inflammatory effects of cortisol on the immune system?
induces lipocortin
inhibits production of interleukin-2
inhibits release of histamine
Exogenous steroids are given when
to suppress immune system and prevent rejection of transplanted organs
combat hyper-immune functions
What are some weak androgens in the zona reticularis?
dehydroepiandrosterone (DHEA)
DHEA sulfate
androstenedione
What enzyme is important for androgen production in the adrenal cortex?
17,20-lyase
What are the symptoms of Cushing’s syndrome?
polydipsia, polyuria, panting, obesity, muscle weakness, alopecia, thin skin
What are the causes of Cushing’s syndrome?
pituitary-dependent hyperadrenocorticism (PDH) with bilateral adrenal hyperplasia
pars intermedia dysfunctioin
adrenal tumors
iatrogenic hyperadrenocorticism resulting from chronic excessive exogenous steroid administration
What does PDH with bilateral adrenal hyperplasia cause?
excess cortisol production
The pituitary adenoma secretes excess _____
ADH
T/F: Addison’s disease occurs usually in older dogs
FALSE - young to middle-aged
What are the causes of Addison’s disease?
auto-immune
infiltrative disease (cancer, cells found in a place it shouldn’t be)
idiopathic
iatrogenic steroids
What happens in Addison’s disease?
loss of aldosterone
loss of cortisol
When there is a loss of aldosterone in Addison’s disease, there is an [increase/decrease] in K+, [increase/decrease] in blood volume, [increase/decrease] in Na+. What else are symptoms?
increase
decrease
decrease
brachycardia
irregular heartbeat
circulatory collapse
A loss of cortisol in Addison’s disease causes
decreased gluconeogenesis
decreased blood glucose
What is the treatment for Addison’s disease?
saline/dextrose solutions
dexamethasone
insulin (as long as glucose is administered, mineral corticoids)
What is the primary form of hyperaldosteronism?
can have idopathic hyperplasia (bilateral)
- tumor (unilateral or bilateral)
What is the secondary form of hyperaldosteronism?
liver disease
kidney disease (activate RAAS pathway, reabsorbs lots of Na+ and H2), increase blood pressure)
What are clinical signs of hyperaldosteronism?
increased ECF volume, increased renal perfusion pressure
What adrenal cortex dysfunction is common in cats?
hyperaldosteronism
Define Alopecia X
elevation in androgens and/or sex steroids
What breeds is alopecia x common in?
Pomeranian, poodles, yorkies, nordic breeds
T/F: Alopecia X only affects males.
FALSE - affects both
What is another name for alopecia X?
atypical hyperadrenocorticism
What happens during alopecia x?
hair cycle arrest
growth-hormone responsive alopecia
castration-responsive alopecia
Where does hair loss first begin?
trunk and caudal thighs
guard hairs lost first
What happens to the skin in alopecia x?
it becomes hyper pigmented
