Adrenal Flashcards
Cortex is from:
Medulla is from:
mesoderm
neural ectoderm
Zona glomerulosa:
Zona fasciculata:
Zona reticularis:
- mineralocorticoids (aldosterone)
- glucocorticoids + androgens (cortisol and corticosterone)
- gonadocorticoids + glucocorticoids (DHEA)
Rate-limiting step of cholesterol synthesis:
First step, CYP11A1 or cholesterol desmolase
- cholesterol to pregnenolone
What is 21-hydroxylase deficiency?
An adrenogenital syndrome
Most common congenital adrenal hyperplasia (a missing enzyme necessary for steroid synthesis) CAH
- Cortisol, corticosterone, aldosterone deficiency
- Increase in ACTH (hypertrophy and high androgens)
- Virilization of female
- Dehydration, shock, hypoglycemia, hyperpigmentation, high Na, low K
Aldosterone action:
Reduce excretion of Na is distal tubule (secrete K and H)
Stimulated by low blood volume/pressure, low Na, high K, ACTH, angiotensin II
** ANP inhibits zone glomerulosa
Conn’s syndrome?
Primary hyperaldosteronism
- adenoma, nodular hyperplasia of zona glomerulosa
- Treatment: surgical for adenoma, receptor antagonist for hyperplasia (spironolactone)
- symptoms: headache, hypokalemia (m. weakness), hypernatremia, hypervolemia, etc.
Secondary hyperaldosteronism:
Cirrhosis, ascites, nephrotic syndrome
Some functions of cortisol:
- Increase bone resorption
- Decrease muscle mass, maintain function
- Wakefulness, emotional tone
- Inc GFR and water clearance
- Fetal maturation
- Dec connective tissue
- Inhibit inflammatory / immune responses
- Maintain CO, increase arteriolar tone, dec endothelial permeability
ACTH produced via processing of…
POMC (prepro-opiomelanocortin)
other products:
- beta and gamma lipotropin
- beta-endorphin (bind to opioid receptors)
- alpha-melanocyte-stimulating hormone (alpha-MSH)
What is Addison’s disease?
Primary adrenal insuffiency
Lack cortisol and therefore negative feedback to ACTH
- -> HIGH ACTH
- Autoimmune
- skin will darken (alpha-MSH from POMC)
- tiredness, weight loss
- LOW aldosterone and cortisol, HIGH renin
Treatment: cortisol and aldosterone
Some things that stimulate ACTH secretion?
- CRH and ADH (from hypothalamus)
- Stress
- Hypoglycemia
Circadian pattern of release (highest in AM)
Causes of adrenal insufficiency:
- Congenital adrenal hyperplasia
- Addison disease
- Infection (TB, sepsis)
- Adrenoleukodystrophy
What is Addisonian crisis?
Life-threatening; severe vomiting/diarrhea and dehydration, low BP and shock, hypoglycemia, loss of consciousness
Treatment: IV fluids and IV hydrocortisone
What is nonclassical CAH?
congenital adrenal hyperplasia
- Residual enzyme activity
- Non-salt losing
- Late childhood precocious pubic hair, clitoromegaly, accelerated growth
In adults, could cause hirsutism / infertility
Screening for CAH?
17-hydroxyprogesterone blood level
