L72: HPA Axis & Adrenal (part 1) Flashcards
Which of the following is NOT regulated by the HPA axis?
A. Short-term adaptive response to stress
B. Long-term adaptive response to stress
C. Anti-inflammatory response
D. Maintenance of K+/Na+/H20 balance
D.
CRF/CRH is made in what nucleus of the hypothalamus?
A. Paraventricular nucleus (PVN)
B. Arcuate nucleus (ARC)
C. Pre-optic area (POA)
D. Supraoptic nucleus (SON)
A. PVN
Biosynthesis of which of the following is NOT regulated by ACTH?
A. Pregnenalone
B. StAR
C. Cholesteral esterase
D. Size and number of adrenal cortical cells
E. Aldosterone in Z. glomerulosa
E. Aldosterone in Z. glomerulosa
What kind of tissue is indicated here?
Glandular tissue of the adrenal cortex
What kind of tissue is indicated here?
Neural tissue of the adrenal medulla
What hormones are being made here?
A. Aldosterone
B. Cortisol
C. DHEAS
E. Pregnenalone
F. Aldosterone and Pregnenalone
F. Aldosterone and pregnenalone
…since this is the Z. glomerulosa
What hormones are being made here?
A. Aldosterone
B. Cortisol
C. DHEAS
E. Pregnenalone
F. Cortisol and Pregnenalone
F. Cortisol and Pregnenalone
…since this is the Z. Fasciculata
What hormones are being made here?
A. Aldosterone (mineralocorticoids)
B. Cortisol (glucocorticoids)
C. DHEA (androgens)
D. Pregnenalone
E. Hormones derived from Tyrosine
Since this is the adrenal medulla
E. Hormones derived from Tyrosine (catecholamines)
Note: indolamines are derived from Tryptophan
Which of the following is released in a CIRCADIAN manner?
A. Aldosterone
B. Cortisol
C. ACTH
D. CRH
B. Cortisol
Which of the following is released in a PULSATILE manner?
A. Aldosterone
B. Cortisol
C. ACTH
D. CRH
D. CRH
Which of the following does NOT decrease serum cortisol binding globulin (CBG) levels?
A. Estrogen
B. Progesterone
C. Shock
D. Severe infection
B. Progesterone
Which of the following is NOT an effect of cortisol on cells harboring 11-beta HSD1?
A. Increase GLUT4 on membrane
B. Increase PEPCK
C. Increase Glucose 6-phosphatase
D. Increase tyrosine aminotransferase
A.
Should be DECREASED GLUT4 since cortisol acts to raise serum Glucose levels, in opposition to insulin
What is cortisol’s action on muscle?
Promotes proteolysis through increased expression of E3 ubiquitin ligase and MuRF-1
What is cortisol’s action on adipocytes?
Increased lipolysis through MAG lipase and hormone-sensitive lipase (HSL).
Redistributes fat stores from limbs to abdomen.
Describe the anti-inflammatory effects of glucocorticoids
Cortisol-GR promotes transcription of IKB, which sequesters NFKB
Cortisol-GR also sequesters NFKB directly
How do prostaglandins promote edema?
Prostaglandins promote capillary permeability
What inhibits prostaglandins, thereby suppressing edema?
Cortisol
Cortisol _______ neutrophil function.
Antagonizes
Cortisol promotes atrophy of
thymus by inhibiting T-cell proliferation
T/F: Cortisol suppresses the humoral response
True
Regarding cortisol’s effect on bone, which is FALSE:
A. it inhibits the synthesis of IGF1 receptors on bone
B. It promotes synthesis of Ca2+ receptors on lumenal side of intestinal epithelial cells
C. Increases bone resorption - activation of osteoclasts
B. is false. Cortisol inhibits synthesis of Ca2+ receptors. We’re trying to stop calcium absorption in gut!
Cardiovascular effects of cortisol
- stimulate RBC production
- Constricts peripheral vasculature by increasing a-adrenergic R
- dilate coronary a. by via increased b-adrenergic R
- Maintain vascular integrity and reactivity
Whats the difference between Cushings disease and Cushing’s syndrome?
Cushing’s disease refers to high cortisol due to pituitary adenoma (excessive ACTH).
Syndrome refers to all phenotypic effects of excess cortisol (low ACTH)
Which has low ACTH levels: Cushing’s disease or syndrome?
Cushing’s syndrome. Since cortisol levels are high, negative feedback lowers ACTH.
Whereas Cushing’s disease implies pituitary adenoma and hence high ACTH.
Why do you get hypertension in cushing’s syndrome?
Excess cortisol activates MR
Why is there glucose intolerance in Cushing’s syndrome/disease?
Excess cortisol antagonizes insulin action.
Why do you get osteoporosis with Cushing’s?
Inhibition of intestinal Ca2+ absorption by decreased lumenal Ca2+ transporters…
Why do you get purple striae in Cushing’s?
Fat redisribution to abdomen stretches skin; may hemorrhage
What can happen with chronic glucocorticoid therapy?
A. Atrophy of Z. Glomerulosa
B. Atrophy of Z. Fasciculata
C. Atrophy of Z. Reticularis
B.
High levels of cortisol negatively feedback on hypothalamus and pituitary. Thus, low CRH and ACTH. Z. Fasciculata is not receiving any input.
How does cortisol promote lung functionin pre-term infants?
increase surfactant
Addison’s disease
autoimmune destruction of adrenals
What is the relative potency of cortisol for GR, versus MR?
1:1
Which of the following synthetic glucocorticoid analogues preferentially activates MR, not GR?
A. Prednisone
B. Methylprednisone
C. Dexamethasone
D. Fludrocortisone
D.
Which of the following synthetic glucocorticoid analogues has no MR activity whatsoever?
A. Prednisone
B. Methylprednisone
C. Dexamethasone
D. Fludrocortisone
C.
Adrenal insufficiency (AI) implies
A. Failure to secrete glucocorticoids
B. Failure to secrete mineralocorticoids
C. Both A and B
Sudden cessation of 30mg hydrocortisone, 7.5 mg prednisone, 0.75 mg dexamethasone, after 3+ weeks of usage.
Adrenal insufficiency. It takes about 3+ weeks at that dosage for adrenal gland to atrophy.
