Hormone Action & Signal Transduction

Question 1

effect of glucocorticoids

Answer 1

accelerated gene transcription

Question 2

effect of thyroid hormone

Answer 2

activation of gene transcription

Question 3

where does hormone-receptor interaction happen in Group I hormones/lipophilic hormones?

Answer 3

cytoplasm, nucleus

Question 4

G(s) stimulates

Answer 4

adenylyl cyclase

Question 5

G(i) inhibits

Answer 5

adenylyl cyclase

Question 6

G(q) stimulates

Answer 6

phospholipase C

Question 7

what happens once adenylyl cyclase has been stimulated?

Answer 7

cAMP nucleotide is formed from ATP.

Question 8

1st intracellular signal recognized in mammalian cells

Answer 8

cAMP

Question 9

adenylyl cyclase composition

Answer 9

receptor - R(s) or R(i)

regulatory complex - G(s) or G(i)

Question 10

how does cholera affect the alpha subunit of GPCR?

Answer 10

it modifies alpha subunit, blocking hydrolysis of GTP back to GDP; therefore, a-GTP remains in active form.

Question 11

cholera toxin: a-GTP always active results to?

Answer 11

severe diarrhea due to persistently high cAMP levels

CFTR channels are stimulated to open –> Cl- + Na + Water leave cell

Question 12

Hormones that inhibit adenylyl cyclase (4)

Answer 12

• acetylcholine
• a2 adrenergics
• angiotensin II
• somatostatin

Question 13

after cAMP is produced from ATP, what happens next? (GPCR)

Answer 13

cAMP activates protein kinase A

Question 14

protein kinase A composition

Answer 14

2 regulatory subunits (R2)

2 catalytic subunits (C2)

Question 15

active C subunit of PKA catalyzes?

Answer 15

transfer of gamma phosphate of ATP to serine or threonine residue –> PHOSPHORYLATION

Question 16

how is PKA activated? (GPCR)

Answer 16

cAMP binds to regulatory unit of cAMP –> R2C2 dissociate, activating C2

Question 17

enzymes that terminate physiologic response of activated GPCR

Answer 17

phosphatases

phosphodiesterase

Question 18

how does phosphodiesterase terminate physiological response of activated GPCR?

Answer 18

hydrolyzes cAMP to 5’-AMP

Question 19

what peptides are produced by cardiac atrial tissues?

Answer 19

atriopeptins

Question 20

atriopeptins bind and activate?

Answer 20

guanylyl cyclase (increasing cGMP levels)

Question 21

elevated cGMP due to atriopeptins result to

Answer 21

natriuresis
diuresis
vasodilation
inhibition of aldosterone secretion

Question 22

what other substances activate guanylyl cyclase?

Answer 22

nitroprusside
nitroglycerine
nitric oxide
na nitrite
na azide

Question 23

can sildenafil (viagra) be given to pts taking nitrates?

Answer 23

no b/c it will potentiate to the vasodilating effect due to increased cGMP level.

Question 24

IKK complex composition (NF-KB)

Answer 24

2 alpha subunits
2 beta subunits
2 gamma subunits