Flashcards in Endo - Adrenal Deck (55)
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1
long term stress response (glucocorticoids)
1. protein/fat converted to glucose or broken down for energy
2. increased blood glucose
3. suppress immune
2
adrenal zones (+hormones)
zona glomerulosa (aldosterone)
zona fasciculata (cortisol + androgens)
zona reticularis (cortisol + androgens)
medulla (E/NE)
3
making E/NE
tyrosine --> dopa --> dopamine --> NE --> E
cortisol needed to make E from NE
4
E:NE release
4x more E
more important for beta 2 receptors
5
embryonic origin of adrenal gland
cortex (mesoderm)
medulla (neuroectoderm)
6
adrenal gland innervation
cortex (nearly none)
medulla (SNS)
7
making aldosterone
rate limiting step: Ang II stimulates cholesterol desmolase (chl to pregnenolone)
pregnenolone --> progesterone
--> deoxycorticosterone (#2 most potent natural MCC)
--> corticosterone
--> aldosterone
8
making cortisol
rate limiting step: ACTH stimulates cholesterol desmolase (chl to pregnenolone)
pregnenolone / progesterone
+ 17 alphahydroxylase
--> --> cortisol
9
making androgens
rate limiting step: ACTH stimulates cholesterol desmolase (chl to pregnenolone)
pregnenolone / progesterone
+ 17 alphahydroxylase
--> --> androgens
10
why is only aldosterone made in ZG? (not cortisol or androgens)
ZG doesn't have 17-alpha hydroxylase
11
things that stimulate cortisol
ACTH
↓ cortisol levels
Stress
ADH
Serotonin
Sleep-wake transition
α-agonists, β-antagonist
12
things that inhibit cortisol
↑ cortisol levels
Opioids
Somatostatin
13
ACTH effects on adrenal gland
stim production of cortisol, adrenal androgens and aldosterone (slightly)
only cortisol feeds back
adrenal gland hyperplasia (via IGF-1)
14
POMC
preproopiomelanocortin is precursor for ACTH
when ACTH is metabolized it makes MSH
15
cortisol release type
pulsatile
constant in amt released, changes in freq
summation for larger pulses
16
cortisol diurnal pattern
ACTH + cortisol peak before waking
lowest before sleep
17
what determines circadian rhythm
suprachiasmatic nucleus
18
things that alter suprachiasmatic nucleus
chronic GCCs (blunt morning peak)
lack of natural light during day, artificial light at night
variable work schedule*
19
cortisol and stress
stress overrides negative feedback
enhance activity of CRH-ACTH system
20
cortisol transport
bound in blood
corticosteroid-binding globulin (CBG, transcortin) - 75%
albumin - 15-20%
unbound 5%
21
cortisol inactivation
takes place in liver
inactivates and conjugates w/ glucuronide or sulfate to up solubility for kidneys
22
cortisol half life
70 min
23
cortisol mech
1. unbind from transport protein
2. enter cell
3. bind to receptor complex (includes HSPs - heat shock proteins)
4. HSPs released
5. receptor binds to DNA
6. regulates gene expression
24
cortisol effects (time)
lag period - need to synth new protein
last a long time - slow protein turnover
25
cortisol actions (broad)
stim gneo in response to low blood sugar
increase protein/lipid breakdown (makes gneo substrates)
anti-inflammatory
suppress immune response
26
cortisol actions (metabolism)
up gneo
up protein/lipid breakdown
inhibits insulin-stimulated gluc uptake by muscle/adipose (like GH)
blocks suppressive effects pf insulin on hepatic glucose output
-----------> provide brain w/ glucose
27
cortisol w/ protein and fat
direct lipolytic effect is small
permissive for lipolytic action of catecholamines
stim appetite
stim lipogenesis in certain spots (face/trunk)
increase protein breakdown up decrease AA utilization everywhere but liver (down protein synth)
28
cortisol and muscles
basal levels of cortisol needed for normal contractility
excess --> atrophy
29
cortisol and bones
decrease bone formation*:
- down vit D synth
- inhibit making osteoblasts
- up apoptosis of osteoblasts/cytes
increase bone reabsorption
- make cytokines --> activate osteoclasts
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