Hellekant Pituitary

Question 1

Growth hormone is produced by what cells?

Answer 1

Somatotrophs

Question 2

Prolactin is produced by what type of cells?

Answer 2

Mammotrophs

Question 3

What hormones are produced by acidophils?

Answer 3

Growth hormone and prolactin

Question 4

What effect does TRH have on prolactin?

Answer 4

Promotes release of prolactin

Question 5

What effect does somatostatin have on growth hormone?

Answer 5

Inhibition

Question 6

What effect does dopamine have on Growth hormone?

Answer 6

Inhibits GH release

Question 7

What kind of receptor is GHRH receptor?

Answer 7

GPCR - stimulate adenylyl cyclase

Question 8

What type of receptor are the somatostatin receptors?

Answer 8

Gi

Question 9

What type of receptor are the GH receptors?

Answer 9

Transmembrane on target cells - activate JAK/STAT

Question 10

When growth hormone acts on the liver, what happens?

Answer 10

The liver produces insulin-like growth factor - 1

Question 11

What are the actions of growth hormone?

Answer 11

Promotes muscle mass and longitudinal (linear) bone growth, can cause hyperglycemia, increases mobilization of fats; acts on liver to increase release of IGF-1

Question 12

How is the growth hormone receptor binding protein produced?

Answer 12

Proteolysis of GHR at the cell surface; thereby releasing its extracellular domain

Question 13

What effects does IGF-1 have?

Answer 13

Increases cartilage growth

Question 14

Severe GH deficiency in children leads to what?

Answer 14

Proportional dwarfism

Question 15

What is the pathogenesis behind proportional dwarfism?

Answer 15

Severe GH deficiency

Question 16

What is Laron syndrome?

Answer 16

AR GHR variant with insensitivy to GH; imparts resistance to CA and DM and prolongs life

Question 17

What condition is caused by gene mutation in the GH receptor, resulting in insensitivity to GH?

Answer 17

Laron syndrome

Question 18

What are the symptoms of GH def in adults?

Answer 18

Generalized obesity, reduced muscle mass, asthenia, reduced cardiac output

Question 19

What does the insulin tolerance test tell you?

Answer 19

Give insulin, create hypoglycemia, and should see increased cortisol from the adrenals, and increased GH from anterior pituitary; failure to respond may suggest need for GH or glucocorticoids

Question 20

What is sermorelin?

Answer 20

GHRH analog

Question 21

What tests can be used to assess GH deficiency?

Answer 21

Insulin tolerance test or GHRH analog and arginine co-stimulation test

Question 22

How is the arginine GHRH test done?

Answer 22

Inject arginine over 30 minutes, inject GHRH over 1 minute, measure serum GH over the next hour; should see GH > 8, if less suggests GH def

Question 23

What is the mot common pituitary hormone deficiency in children?

Answer 23

Growth hormone

Question 24

What is an early sign of GH deficiency in children?

Answer 24

Hypoglycemia - due to unopposed action of insulin

Question 25

What are the therapeutic uses of GH in adults?

Answer 25

GH def, wasting in patients with HIV, short bowel syndrome

Question 26

Why is GH used in short bowel syndrome in patients receiving specialized nutrition support?

Answer 26

Improved mucousal integrity and thus GI function

Question 27

What is somatropin?

Answer 27

Recombinant human growth hormone

Question 28

When using rhGH in adults, what labs should be monitored?

Answer 28

Lipid profile, fasting glucose, bone density

Question 29

In Laron-type dwarfism, low levels of what are seen?

Answer 29

IGF-1; GH does not have effect on GHR on liver

Question 30

What is mecasermin?

Answer 30

Aka increlex = rh IGF-1

Question 31

What is mecasermin rinfabate?

Answer 31

Complex of rhIGF-1 + IGFBP3

Question 32

What is Iplex?

Answer 32

Mecasermin rinfabate - complex of rhIGF-1 + IGFBP3

Question 33

What are the drug names for rhIGF?

Answer 33

Mecasermin (increlex) or mecasermin rinfabate (iplex)

Question 34

What is IGFBP3?

Answer 34

IGF carrier protein

Question 35

When should rhIGF be avoided?

Answer 35

Children with cancer; in patients with closed epiphyses

Question 36

Hypersecretion of GH in adults is most commonly due to what?

Answer 36

GH secreting anterior pituitary adenoma

Question 37

Abnormal growth of what tissues is seen in hypersecretion of GH?

Answer 37

Abnormal growth of cartilage, bone, skin, muscle, heart, liver, GI

Question 38

What is usually first indication of GH hypersecretion?

Answer 38

Elevated IGF-1

Question 39

How is GH hypersecretion confirmed?

Answer 39

Elevated GH level 2 hours after glucose administration

Question 40

During sleep, how does a patient with acromegaly differ from a "normal" patient?

Answer 40

GH levels do not show circadian rhythm or peaks and nadirs, but are within normal range

Question 41

How is GH hypersecretion treated?

Answer 41

GH inhibitory hormones: somatostatin and dopamine

Question 42

What dopamine receptor is targeted in treatment of GH adenoma?

Answer 42

D2

Question 43

What is octreotide?

Answer 43

Somatostatin analog (long acting)

Question 44

What is pegvisomant?

Answer 44

PEG derivative of mutant GH; binds GH receptor and blocks downstream events

Question 45

What is one of the problems encountered when using pegvisomant?

Answer 45

Blocks GHR on liver, decreasing IGF-1 release, but then increasing GH secretion due to loss of negative feedback

Question 46

What drug is a GH antagonist?

Answer 46

Pegvisomant

Question 47

What dopamine analogs are used in the treatment of pituitary adenoma that is secreting prolactin/growth hormone?

Answer 47

Bromocriptine and cabergoline

Question 48

What is the MOA of bromocriptine?

Answer 48

Dopamine analog at D2 receptor

Question 49

What is the MOA of cabergoline?

Answer 49

Dopamine analog at D2

Question 50

What effect does VIP have on prolactin?

Answer 50

Promotes release

Question 51

What effect does TRH have on prolactin?

Answer 51

Promotes release

Question 52

What is the primary inhibitor of prolactin release?

Answer 52

Dopamine

Question 53

What do mammotrophs produce?

Answer 53

Prolactin

Question 54

What type of receptor does prolactin bind?

Answer 54

Transmembrane proteins that activate JAK/STAT family; tyrosine kinase

Question 55

What form of the prolactin receptor is the active form?

Answer 55

Long form

Question 56

What form of the prolactin receptor is acts as a dominant negative form?

Answer 56

Short form

Question 57

What are the physiologic effects of prolactin?

Answer 57

Breast development during pregnancy, milk secretion during lactation

Question 58

What effect does prolactin have on breast tissue?

Answer 58

Expansion of lobular-alveolar development during pregnancy

Question 59

During pregnancy, what is inhibiting lactation?

Answer 59

High levels of progesterone

Question 60

Hypersecretion of prolactin in males results in what?

Answer 60

Impotence

Question 61

Hypersecretion of prolactin has what effects on hormones?

Answer 61

Inhibits GnRH, and therefore decreases gonadal hormones

Question 62

What is the preferred treatment of prolactinoma?

Answer 62

Cabergoline - dopamine agonist; high efficacy

Question 63

What receptors are targeted in treatment of prolactinoma?

Answer 63

D2