The Adrenal Gland- Functions and Diseases Flashcards
the adrenal medulla is of _____ origin
ectodermal
the adrenal cortex is of _____ origin
epidermal (mesoderm)
what does the adrenal cortex secrete
aldosterone
cortisol
androgens
what does the adrenal medulla secrete
catecholeamines
what is the main secretory product of the zona glomerulosa
mineralocorticoid (aldosterone)
what is the main secretory product of the zona fasciculata
glucocorticoids (cortisol)
androgens
what is the main secretory product of the zona reticularis
glucocorticoids (cortisol)
androgens
what is the main product of adrenal medulla
catechole. norep and epin
this protein is involved in the rate limiting step in production of steroid hormones by transporting cholesterol into the mitochondria
StAR
____ converts cholesterol into ___ (first enzyme)
desmolase, pregnenolone
what enzymes are in the aldosterone arm
21 B hydroxylase
11 B hydroxylase
what enzyme is in all 3 arms: aldosterone, cortisol, androgens
3B hydroxysteroid dehydrogenase
what enzymes are in the cortisol arm
21 B hydroxylase
11B hydroxylase
17 a hydroxylase
what enzymes are in the androgen arm
17 a hydroxylase
17,20 lyase
a loss of the 21 B hydroxylase enzyme will lead to what?
pregnenolone sent to make androgens, no negative feedack for sex hormones
- virulization of fetus
- lose cortisol
- hyponatremia and hypovolemia (no aldost)
- congenital adrenal hyperplasia (95% of cases)
17a hydroxylase deficiency
- pregnenolone is directed towards mineralocorticoid synthesis
- lose secondary sex characteristics
ACTH is derived from post-translational processing of ____
POMC
POMC is broken down into ___ and ___ one of which increases __
ACTH and a-MSH
-a-MSH increases melanin synthesis
cortisol has a negative feedback on what
and what kind of feedback loop is this (long or short)
hypothalamus (-) CRH Anterior pituitary (-) ACTH
-long loop negative feedback
when is cortisol released the most?
in the morning and is around 20 mircrograms/dl
what can exogenous administration of cortisol due to certain cells
may shut down ACTH production and adrenal cells that produce cortisol atrophy
what does exogenous cortisol do to CRH,ACTH,Cortisol
decreases all of them
cushings syndrome is what and has what effects on CRH, ACTH, and cortisol
SYNDROME: tumor of the adrenal gland, unregulated secretion of cortisol
-decreases CRH and ACTH
cushings disease is what and has what effects on CRH, ACTH, and cortisol
DISEASE: tumor of the anterior pituitary
- increased ACTH, and cortisol
- decreased CRH
- ACTH has trophic effect on adrenal gland too
addison’s disease and cortisol and what is primary vs secondary
causes hypocortisolism
- primary is autoimmune attack of adrenal gland
- secondary is from chronic exogenous glucocorticoid treatment
cushings syndrome symptoms
buffalo hump on back of neck
moon face
excess weight gain in abdomen
dark red or purple stretch marks
angiotensin ___ can constrict blood vessels to increase BP
II
what is the direct effect of aldosterone secretion
ACTH
what is the secondary stimulation of aldosterone secretion
angiotensin II
steps in action of aldosterone in renal sodium resab
1) aldosterone from blood enters P cell of distal nephron and binds aldosterone receptor
2) hormone-receptor complex goes to nuclues and txn occurs for mRNA
3) translation of mRNA to make epithelial sodium channels and potassium channels
- potassium out
- sodium in
4) alters the activity of the Na+/K+ ATPase at the basolateral end to pump out sodium and bring in more K+
conn’s syndrome
primary hypealdosteronism, adenoma in the adrenal cortex
secondary hyperaldosteronism
excessive renin secretion by the juxtaglomerular cells in the kidney
hypoaldosteronism causes (3)
destruction of the adrenal cortex
defects in aldosterone synthesis
inadequate stimulation of aldosterone secretion
what cells of the adrenal medulla produce catecholeamines
chromaffin cells
adrenal medulla produces primarly ___ and small amounts of __
epinephrine (80%)
norepinephrine (20%)
synthesis of catecholamines
tyrosine–>DOPA–>Dopamine–>norep–>epin
what enzyme converts norepinephrine to epin and what stimulates this
PNMT and cortisol stimulates this
___ stimulates the synthesis of DOPA
ACTH
steps of norep and epin synthesis and locations
1) tyrosine to DOPA to Dopamine in the cytosol
2) Dopamine enters chromaffin granule through VMAT-1
3) Dopamine Beta hydroxylase converts to NE in granule
4) NE leaves granule through VMAT1 and is converted to epin by PNMT in cytosol
5) epin back into granule through VMAT1 and stored in complex
the storage complex in the chromaffin granule contains what
ATP, Ca2+, NE, Epi, inside a chromogranin
what is the RL step in NE and E synthesis
hydroxylation of tyrosine by tyrosine hydroxylase to produce DOPA
Tyrosine —tyrosine hydroxylase—> DOPA
what are chromogranins and what can they be used to mark
complexes that decrease osmotic burden of storing individual molecules of E within chromaffin granules
-can be marker of sympathetic paraganglion-derived tumors (paragangliomas)
what can be measured to determine total catecholamine production
VMA
epinephrine is degraded by _____ (enzyme) and turned into ___
COMT, metanephrine
norepinephrine is degraded by ____ (enzyme) and turns to ___
COMT, normetanephrine
normetanephrine and metanephrine are converted to ___ by what enzyme
VMA by MAO
which receptors respond better to NE than E
a1,a2 and B3
which receptors respond equal to NE and E
B1
which receptors respond better to E than E
B2
what are the 3 main symptoms of pheochromocytoma
headaches, sweating, palpitations
what is a pehochromocytoma
tumor of chromaffin tissue
short term stress stimulates adrenal medulla via what
preganlionic sympathetic fibers (catechole released)
prolonged stress response from what
ACTH from AP
17a hydroxylase deficiency leads to what presentation
male: ambiguous genitalia, undescended testes
female: lacks secondary sexual development
21 hydroxylase deficiency presentation
presents in infancy as salt wasting (hypotension),
hypoglycemia
childhood has precociouis puberty
XX: virulization
**most common CAH
11 B hydroxylase defeciency effect on BP
decreases aldosterone but increaess 11-deoxycorticosterone which increases blood pressure
11 B hydroxylase deficiency presentation
XX: virilization
what is common presentation with all congenital adrenal hyperplasias
enlargement of both adrenal glands due to increaseased ACTH stimulation in response to low cortisol
