3.4 Prolactin (PRL)

Question 1

What is the mammotropic hormone?

Answer 1

Prolactin (mammotropic…mammary glands…lactate…prolactin…just think about it)

Question 2

What hypothalamic hormone promotes prolactin secretion from the anterior pituitary?

Answer 2

Prolactin Releasing Hormone (PRH)

Question 3

What hormone is the primary inhibitor of prolactin secretion?

Answer 3

Dopamine

Question 4

What kind of receptor does prolactin bind to?

Answer 4

JAK/STAT –> cascade of tax events

Question 5

What are the effects of prolactin?

Answer 5

Immunity and autoimmunity (…ok)
Breast development during pregnancy
Milk secretion during lactation

Question 6

When is the peak prolactin level?

Answer 6

During nursing 2-3 orders of magnitude higher

Question 7

What is the overall effect of blocking the pituitary portal system?

Answer 7

INCREASED secretion of PROLACTIN (no negative feedback)

DECREASED secretion of ALL OTHERS

Question 8

What are some potential causes of hypersecretion of prolactin hormone?

Answer 8

Pituitary tumors
Tumor that disrupts tonic inhibition
Iatrogenic: dopaminergic blocking agents
Injury/lesion

Question 9

What are the symptoms of prolactin hypersecretion?

Answer 9

Males: impotence, lactation
Females: Amenorrhea, galactorrhea, infertility, lactation

Question 10

How can prolactin hypersecretion be treated?

Answer 10

Dopamine agonists (carbergoline or bromocriptine)

Question 11

Which dopamine agonist is preferred for pituitary tumors? Why?

Answer 11

Carbergoline

Higher efficacy in normalizing prorating levels
More likely to shrink pituitary tumor

Question 12

What are some potential side effects of carbergoline?

Answer 12

N/V, dizziness, and orhostatic hypotension

Stroke and psychiatric manifestations (not used t prevent postpartum lactation)

Question 13

Does prolactin have any therapeutic uses?

Answer 13

Not currently…may be used for lactation insufficiency