Adrenal Gland Flashcards
Glucocorticoids, mineral corticoids, and catecholamines are released from what gland?
Adrenal gland
Blow flood from suprarenal arteries creates a sinusoid system in the adrenal medullae, this help modulate what?
Enzyme activity
What are the 3 layers of the adrenal cortex?
- Z. glomerulosa (outer most)
- Z. fasciculata
- Z. reticularis (inner most)
“Go Find Rex, Make Good Sex”
T or F: All steroids share the same first step (cholesterol converted to prenenolone via desmolase)?
True
Mobilization of cholesterol (via ATII receptor, K+ channels) → free cholesterol travels to mitochondria → inner mitochondrial membrane (via STaR) → converted to pregnenolone via desmolase (this is the rate limiting step and dependent on STaR)
What are the rate limiting enzymes in the conversion of cholesterol to pregnenolone?
Desmolase, dependent on STaR
The Z. glomerulosa produces what hormones?
mineralcorticoid: Aldosterone
T or F: Aldosterone provide negative feedback on CRH & ACTH
FALSE
Cortisol is the only corticoid that provides negative feedback on CRH & ACTH
The Z. glomerulosa lack what enzyme forcing pregnenolone to only be converted to progesterone => aldosterone?
Lacks 17𝛂-hydroxylase
MR type 1 receptors are greatest in what organ?
Kidney
What hormones stimulates ACTH to produce aldosterone?
ATII (RAAS)
What layer of the adrenal cortex lacks 17,20-lyase (prevents production of androstenedione) and lacks aldosterone synthase (prevents production of aldosterone)?
Z. fasciculata
T or F: GR Type II receptors are located in all cells?
True
The cortisol-cortisone shunt includes what two enzymes?
11B-HSD1 (activates: cortisone to cortisol)
11B-HSD2 (inactivates: cortisol to cortisone)
Liver cortisol → kidney where inactivated by 11B-HSD2, cortisone can’t bind to MR → cortisone travels back to liver → activated by 11B-HSD1 → binds to GR receptors
What hormones lead to the production of cortisol?
GnRH → CRH → ACTH → Cortisol (glucocorticoid)
T or F: Cortisol provide negative feedback to GnRH, CRH, and ACTH
TRUE
What corticoids produce a long term response to stress?
Mineralocorticoids (aldosterone) and glucocorticoids (cortisol)
What enzyme does Z. reticularis lack preventing production of aldosterone and cortisol?
21𝛽 Hydroxylase
What hormone class does Z. reticularis produce?
Androgens (androtenedione)
Do angrogens have feed back on CRH and ACTH?
No
Cortisol is the only hormone that has negative feedback on CRH and ACTH
The following are a result of a deficiency of what enzyme?
- No conversion of: progesterone → 11-deoxycorticosterone OR 17-hydroxyprogesterone → 11 deoxycortisol
- Cortex does NOT produce glucocorticoids or mineralocorticoids → sodium loss and hypoglycemia
- Steroid intermediates build up → converted to androgens → Adrenogenital syndrome & ↑ 17-ketosteroids in urine
- ↑ ACTH (b/c lack of neg feedback from cortisol) → tropic effects
21𝛽 Hydroxylase Deficiency
Plasma levels of Cortisol and what other hormone are reflect pulsatile and circadian release of ACTH?
Cortisol and Androtenidione (Androgens)
Androstenedione are a major source of androgens for females, these produce what effect in the female? (2)
secondary sex charactristics and libido
Does catecholamine synthesis take place in the adrenal cortex or medulla?
Medulla (specifically chromaffin cells)
What is the rate limiting step in catecholamine synthesis?
Tyrosine conversion to DOPA via tyrosine hydroxylase
Tyrosine conversion to dopamine takes place in the cytosol or granules?
Cytosol
Dopamine conversion to NE takes place in the cytosol or granules?
Granules
NE conversion to E takes place in the cytosol or granules?
Cytosol
What enzyme is responsible for conversion of NE to E?
phenylethanolamine-N-methyltransferase
Where is Epi store in the body?
Granules
Activation of tyronsine hydroxylase is a result of acute or chromic stimulation of catecholamine synthesis?
Acute