Monday - Pituitary phys and pharm - Trachte Flashcards Preview

Josh Endo week 1 > Monday - Pituitary phys and pharm - Trachte > Flashcards

Flashcards in Monday - Pituitary phys and pharm - Trachte Deck (29):
1

What 2 hormones regulate Growth Hormone (somatotropin) release

Growth Hormone releaseing Hormone (GHRH)

Growth Hormone Inhibiting Hormone (GHIH) = somatostatin. Uses Gi receptors --> K channels activated

Also, Dopamine inhibits GH

2

How does GHRH work?

G protein S
Adenylyl cyclase --> increase cAMP --> release GH

3

How is growth hormone transported?

bound to GH binding protein, which is a part of the receptor that has been cleaved off. how efficient.

4

What kind of intracellular signaling does the GH receptor use?

tyrosine kinase --> dimerization --> JAK/STAT --> activation of things in nucleus for metabolism, growth, proliferation and differentiation.
(TYRannOSaurus is large (GH))

5

What hormone has the same effects as GH

Insulin-like Growth Factor-1 (IGF-1, somatomedin)

6

What does GH do to each of these?
Sodium
insulin sensitivity
fat stores
protein synthesis
epiphysial growth

Sodium --> retention
insulin sensitivity --> decrease
fat stores --> lipolysis
protein synthesis --> promotes
epiphysial growth --> obviously promotes

also increases IGF-1 production

7

In what ways to GH and IGF-1 oppose each other?

GH - decreases insulin sensitivity, but IGF-1 has insulin activity

GH - lipolysis
IGF-1 --> anti-lipolysis

8

Why did Barry Bonds need to get a bigger helmet?

Because he's a cheater. (he took growth hormone) better put an asterisk by all his stats, am I right?

9

What happens to carbohydrate metabolism in response to GH

body decreases carb utilization, decreases uptake --> increases level in blood --> secondary release of insulin.
increases fats being used for energy

10

Laron Syndrome

GH receptor insensitive to GH - very short, but resistant to diabetes and cancers

low IGF-1 levels too

11

Proportional Dwarfism is due to what?

decreased GH in kids.
Can be from Laron syndrome
Turner Syndrome
SHOX mutation
poor nutrition
stress

12

Symptoms of GH deficiency

obesity (reduced muscle mass)
reduced energy, weakness
reduced cardiac output

13

Why is it not super useful to measure levels of GH

it changes to much (pulsate pattern)
increases during sleep

IGF-1 is slightly better at measuring GH

14

A way to asses the GH activity using blood sugar levels

inject insulin --> hypoglycemia
GH should be released after this to increase glucose level in blood

15

Analog of GHRH called?

Sermorelin

16

Way to measure production of GH

collect baseline level of GH and IGF-1
inject Arginine
inject GHRH
measure GH over and hour

17

Side effects of giving GH

antibodies to it (its a protein)
Scoliosis
Diabetes

18

Recombinant Human IGF-1 is called?
Use?

Mecasermin
If GH receptor is bad (Laron Syndrome), can induce some growth. Fewer side effects than GH

19

Too much secretion of GH leads to:

Acromegaly

20

Diagnosis of GH hypersecretion

elevated IGF-1
Elevated GH 2 hrs after glucose

21

Treatment for GH hypersecretion

Somatostatin (octreotide) and dopamine (specifically the D2 receptor) (Bromocriptide)

22

Growth hormone antagonist used to treat acromegaly

Pegvisomant
can have liver tox and antibodies to it

23

Regulation of prolactin

Positive
- Prolactin releasing hormone (trachte doesn't believe it exists)
- VIP
- Thyrotropin releasing hormone (TRH)

inhibitory
- Dopamine

24

How does the prolactin receptor work?

prolactin binds to receptor --> dimerizes --> tyrosine Kinase --> Jak/Stat --> trascriptional events

25

Effects of Prolactin

Breast development during pregnancy (lobular development)
Milk secretion during lactation (inhibited by progesterone)

26

What does the hypothalamus tonically do to prolactin levels

inhibits via dopamine (prolactin inhibitory hormone PIH)
D2 receptor

If infundibulum is severed, prolactin increases. others decrease

Also, no negative feedback when it's released

27

What would lead to prolactin hypersecretion?

Prolactin secreting tumor
Tumor that disrupts inhibition
Dopamine blocking agents
Injury to infundibulum

28

Girl. no period. She's lactating all over the place. Doesn't have kids tho.
What's wrong with her?

You may argue, nothing!
But she for sure has prolactin hypersecretion.

29

Treatment of prolactin secreting tumor

Dopamine (D2) agonist (bromocriptine. cabergoline has fewer side effects)