Hormones of the Anterior Pituitary Gland

Question 1

• Initiation and maintenance of lactation

Answer 1

PROLACTIN

Question 2

Prolactin

• Inhibited by_____

Answer 2

dopamine (hypothalamus)

Question 3

Prolactin

Circadian Secretion Pattern:
• Highest levels (zenith): Prolactin secretion peaks during_____, allowing for optimal conditions for lactation preparation.

• Lowest levels (nadir): Prolactin secretion reaches its lowest point between______

Answer 3

sleep

10 am and noon.

Question 4

PROLACTIN
FUNCTION

Answer 4

• Stimulates milk production in the breast (casein, lactalbumin)

• Stimulates breast development (in a supportive role with estrogen)

• Inhibits ovulation by decreasing synthesis and release of gonadotropin-releasing hormone (GnRH)

• Inhibits spermatogenesis (by decreasing GnRH)

Question 5

Prolactin stimulates the mammary glands to produce milk by increasing the synthesis of proteins like (2)

Answer 5

casein and lactalbumin

Question 6

Inhibition of Ovulation: Prolactin reduces the synthesis and release of_______

This reduction lowers the levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), preventing ovulation and acting as a natural contraceptive mechanism during breastfeeding.

Answer 6

gonadotropin-releasing hormone (GnRH)

Question 7

Inhibition of Spermatogenesis: In males, high levels of prolactin decrease____, leading to lower levels of LH and FSH, which can inhibit spermatogenesis (sperm production).

Answer 7

GnRH

Question 8

Factors that Increase Prolactin Secretion

Answer 8

Estrogen (pregnancy)
Breast-feeding
Sleep
Stress
TRH
Dopamine antagonists

Question 9

Factors that Decrease Prolactin Secretion

Answer 9

Dopamine
Bromocriptine (dopamine agonist)
Somatostatin
Prolactin (by negative feedback)

Question 10

PROLACTIN
DISORDERS

• results in the failure to lactate
• Due to pituitary necrosis or infarction

Answer 10

Prolactin Deficiency

Question 11

PROLACTIN
DISORDERS

• results from hypothalamic destruction, or from prolactin-secreting tumors
(prolactinomas).
• causes galactorrhea and decreased libido.
• causes failure to ovulate and amenorrhea because it inhibits
GnRH secretion.

Answer 11

Prolactin Excess

Question 12

• A pituitary tumor that directly secretes prolactin
• Most common type of functional pituitary tumor.

Answer 12

PROLACTINOMA

Question 13

PROLACTIN
TESTING
• Serum half-life:______
• Laboratory
• Screening:____ specimens should be obtained at______ intervals
-_________ assay

Answer 13

26-47 minutes

3

20 to 30-minute

Immunometric assay

Question 14

Prolactin levels are commonly measured using an________. This type of test uses antibodies to detect and quantify the amount of prolactin in the blood.

Answer 14

immunometric assay

Question 15

Dopamine antagonists

Answer 15

Increase prolactin

Question 16

TRH

Answer 16

Increase prolactin

Question 17

Stress

Answer 17

Increase prolactin

Question 18

Sleep

Answer 18

Increase prolactin

Question 19

Breast-feeding

Answer 19

Increase prolactin

Question 20

Estrogen (pregnancy)

Answer 20

Increase prolactin

Question 21

Prolactin (by negative feedback)

Answer 21

Decrease prolactin

Question 22

Somatostatin

Answer 22

Decrease prolactin

Question 23

Bromocriptine (dopamine agonist)

Answer 23

Decrease prolactin

Question 24

Dopamine

Answer 24

Decrease prolacitn