Stress and Metabolism: Epinephrine

Question 1

Adrenal medulla synthesizes

Answer 1

EPI or NE

Question 2

Substrates to EPI and NE are

Answer 2

tyrosine or phanylalanine (aa derivatives)

Question 3

tyrosine hydroxylase

Answer 3

converts tyrosine to DOPA

Question 4

Rate-limiting step in catecholamine synthesis

Answer 4

Tyrosine hyroxylase conversion of tyrosine to DOPA

Question 5

Negative Feedback

Answer 5

EPI and NE inhibit tyrosine hydroxylase

Question 6

DOPA is converted to dopamine and transferred to

Answer 6

chromaffin granule

Question 7

Within the chromaffin granule, dopamine-hydroxylase catalyzes

Answer 7

dopamine to NE

Question 8

In EPI producing cells, NE enters the cytosol and PNMT

Answer 8

converts NE to EPI

Question 9

PNMT is located

Answer 9

in the cytosol of EPI producing cells only

Question 10

Synthesis of PNMT is stimulated by

Answer 10

HIgh levels of cortisol during STRESS

Question 11

How do high levels of cortisol reach the adrenal medulla

Answer 11

by first flowing by the adrenal cortex where cortisol is made

Question 12

Storage of catecholamines

Answer 12

in the chromaffin granules attached to ATP (to protect them from degradation)

Question 13

the chromaffin granule is __________

Answer 13

acidic; DBH catalyzes optimally at acidic pH

Question 14

Activation of the chromaffin granules

Answer 14

SNS fibers innervate the adrenal medulla, stimulation and Ache cause chromaffin granules to fuse with cell membrane and exocytosis occurs (Ca involvement) and EPI concentration will increase

Question 15

Beta 1 receptor in

Answer 15

heart

Question 16

alpha 1 receptor in

Answer 16

blood vessels

Question 17

beta 2 and beta 3 receptors in

Answer 17

tissues with intermediary metabolism, bronchial SM, and heart

Question 18

beta 2 binds

Answer 18

EPI > NE

Question 19

Beta 3 binds

Answer 19

NE > EPI

Question 20

EPI primary action

Answer 20

bind beta 2 receptors for metabolic action: mobilize fuel for stressful situations

Question 21

Epinephrine is a _____________ to insulin

Answer 21

counter-regulatory hormone

Question 22

Stress –> SNS activation–>

Answer 22

EPI release from adrenal medulla –> increased fuel

Question 23

EPI causes

Answer 23

decreased synthesis, increased mobilization, increased gluconeogenesis and glycogenolysis, secretion of glucagon, prevents glucose transport via GLUT4 (Acts like glucagon)

Question 24

What stimuli will cause the SNS to activate EPI release from adrenal medulla?

Answer 24

trauma, circulatory failure, illness, hypoxia, cold exposure, hypoglycemia

Question 25

Autocrine control of catecholamines

Answer 25

release of catecholamines into the synaptic cleft allows the catecholamines to bind alpha 2 receptors in the pre-synaptic nerve terminal, preventing further release and prevents excessive secretion of catecholamines

Question 26

Enzymatic degradation of catecholamines

Answer 26

liver; deamination by MAO and AO

3-O-methylation by COMT

Question 27

Major metabolites of catecholamine degradation are

Answer 27

VMA and MOPEG

Question 28

Uptake 1

Answer 28

NE reuptake by presynaptic neuron and either stored in chromaffin granule or degraded by MAO (COMT in liver)

Question 29

Uptake 2

Answer 29

non-neuronal uptake and degradation by MAO and COMT

Question 30

Metabolites of EPI and NE are excreted in

Answer 30

urine

Question 31

Pheochromocytoma

Answer 31

adrenal medulla tumor producing excessive catecholamines

Question 32

Pheochromocytoma symptoms

Answer 32

increased HR, HTN, tachycardia, headache, sweating, anxiousness, orthostatic hypertension, excessive adrenergic tone, urinary catecholamines

Question 33

Pheochromocytoma treatment

Answer 33

removal of tumor and replacement of mineral/glucocorticoids (not usually NE or EPI)