Somatostatin

Question 1

What are the characteristics of abnormal GH secretion?

Answer 1

GH deficiency, leading to abnormal growth
GH over-secretion (gigantism/acromegaly)
GH during aging

Question 2

What causes GH deficiency?

Answer 2

GH gene defects

Question 3

What are the causes of short stature?

Answer 3

GH deficiency and GHR or signaling defects
IGF-1/IGF-1 receptor defects

Question 4

What is idiopathic short stature?

Answer 4

Short normal people

Question 5

How is idiopathic short stature treated?

Answer 5

GH therapy, however results are not satisfactory

Question 6

What causes gigantism?

Answer 6

Excess pituitary GH synthesis and secretion
Over-secretion of GHRH or mutations in the somatotrope GHRH receptor leading to a tumor

Question 7

Which condition do these features describe?

Excess growth of soft tissues, greasy thick skin, coarse facial features in adults
Insulin resistance, diabetes

Answer 7

Acromegaly

Question 8

Name one therapeutic approach for gigantism/acromegaly

Answer 8

Surgery - remove GHRH or GH tumor
Radiation - reduce or ablate tumor if it is close to the pituitary
Medication - suppress GH secretion and block GH receptor

Question 9

What are the consequences of aging the somatopause?

Answer 9

Slow decline of GH levels in men and sharp decline in women with menopause
Decrease due to lower GHRH and pituitary responsiveness
Increased BMI

Question 10

There is an increased incidence of colorectal polyps and cancer in _____________ patients

Answer 10

Acromegalic

Question 11

High serum GH levels are associated with high risk of breast, prostate, gastric, ________ and lung cancer

Answer 11

Colon

Question 12

High serum IGF-1 levels are associated with high risk of breast, prostate and _________ cancer

Answer 12

Colorectal

Question 13

Which somatostatin receptor is predominant?

Answer 13

Sst2A

Question 14

sst1 receptor is abundant in the ____________ and sst2 is abundant in the __________ pituitary gland

Answer 14

Hypothalamus; anterior

Question 15

What is an example of sst2A and sst5 agonist that helps treat GH release?

Answer 15

Ocetreotide

Question 16

Where is sst1 receptor highly expressed?

Answer 16

Ventro-medial Arc

Question 17

Plasma membrane sst1 receptors are targeted to ____________ zones during GH trough periods

Answer 17

Perisynaptic

Question 18

Plasma membrane sst1 receptors in the _______ localize preferentially to inhibitory symmetric synapses

Answer 18

Arc

Question 19

Which compartment does sst2 traffic to?

Answer 19

Syntaxin-6 positive compartment

Question 20

True or false: Syntaxin-6 positive compartment is found in TGN and recycling endosomes

Answer 20

False, they are spatially distinct

Question 21

Brefeldin A disperses _________ markers but not ___________

Answer 21

TGN; syntaxin-6

Question 22

Which storage vesicle is sst2 similar to?

Answer 22

GLUT4 storage vesicles

Question 23

Recycling of sst2 in __________ corticotropes can be induced by _______

Answer 23

AtT20; CRH

Question 24

Which neuropeptides colocalize in the Arc ?

a) DA and GHRH
b) DA and somatostatin
c) NPY and somatostatin

Answer 24

a)