8. Prolactin Flashcards Preview

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Flashcards in 8. Prolactin Deck (22):
1

prolactin is secretd mainly by

anterior pituitary ( adenohypophysis)

2

prolactin function

1. stimulates milk production ob breast
2. inhibits ovulation in females ( by inhibiting GnRH)
3. inhibits spermatogenesis in males ( by inhibiting GnRH)

3

prolactin effect on hypothalamic pituitary axon

it supresses GnRH secretion

4

pituitary prolactinoma - symptoms

1. amenorrhea
2. osteoporosis
3. hypogonadism ( infertility, decreased libido)
4.galactorrhea

5

prolactin secretion from anterion pituitary is tonically inhibited by

1. dopamine from hypothalamus
2. prolactin by increasing dopamine secretion

6

prolactin secretion is increased by examples

1. TRH (e.g in 1ry or 2ry hypothyroidism)
2. estrogen ( OCP, pregnacy)
3. Dopamine antagonists ( e.g most antipsychotics)

7

dopamine agonist ( for prolactinoma)

bromocriptine
cabergolide

8

Dopamine agonist and its used on hypothalamus - pitutary axis

bromocriptine ( or carbegolide) inhibit prolactin secretion can be used in treatment of prolactinoma

9

dopamine antagonists can cause ( and why ) ( through hypothalamus - pituitary axis )

galactorrhea due to hyperprolactinemia

10

dopamine antagonist example ( group of drugs ) effect on hypothalamus - pituitary axis

1. antipsychotics
2. oral contraceptive pills

they stimulate prolactin secretion

11

prolactin secretion is regulated by

1. TRH ( positively)
2. Dopamine ( negatively)
3. prolactin ( negatively by increasing dopamine secretion )
4. estrogen ( positively, in pregnancy , OCP)

12

prolactin effect on breast

milk production

13

prolactin effect on prolactin secretion ( and pathophysiology )

prolactin inhibits prolactin secretion by increasing of dopamine synthesis and secretion from hypothalamus

14

effects of renal failure in prolactin

increases it via reduced prolactin elimination

15

Dopamine - is inhibited ( and s prolactin is secreted ) via

1. medications
2. Nipple stimulation
3. Chest wall injury ( via ANS)

16

chest wall injury - prolactin

chest wall injury inhibit Dopamin action of prolactin secretion via chest wall injury

17

A woman being treated for schizophrenia complains of breast fullness, galactorrhea, and amenorrhea. What is the likely cause?

Increased prolactin levels secondary to dopamine antagonists (antipsychotics)

18

Why are women less likely to become pregnant when breastfeeding?

Prolactin (necessary for milk production) inhibits ovulation via the inhibition of gonadotropin-releasing hormone (GnRH)

19

A woman with Graves disease undergoes thyroid irradiation and now complains of amenorrhea. How do you treat her?

Hypothyroidism is likely (it increases TRH, induces prolactin secretion, and inhibits GnRH, and therefore ovulation, so give levothyroxine

20

How does prolactin affect fertility in men? From where is it released?

It decreases spermatogenesis by inhibiting gonadotropin-releasing hormone (GnRH) synthesis and release; released from anterior pituitary

21

What inhibits prolactin release? What stimulates it?

Dopamine, estrogens; TRH

22

A man complains of losing peripheral vision. On ROS, he reports decreased libido. What single cause could account for both of these changes?

Prolactinoma compressing the optic chiasm, leading to bitemporal hemianopsia, and secreting excess prolactin, decreasing libido