Endocrine 3: Prolactin Hormone (PRL) + Panhypopituitarism

Question 1

Cells secreting PRL

Answer 1

Mammotrophic acidophilic cells of Anterior pituitary gland

Question 2

Nature of PRL hormone

Answer 2

Polypeptide (199aa), similar in structure to GH

Question 3

Normal levels of PRL

Answer 3

• Male: 5ng/ml
• Female: 8ng/ml

Question 4

Mechanism of Action of PRL hormone

Answer 4

Similar the GH:
* Homodimer receptor complex
* Activates JAK-STAT pathway

Question 5

Enummerate Functions of PRL in females

Answer 5

• increases Caesin & lactalbumin proteins in milk secretion
• inhibit ovulation

Question 6

Describe how prolactin (PRL) inhibits ovulation

Answer 6

it inhibts the effect on gonadotrophic hormones (LH & FSH) on the ovaries

Question 7

Effect of lactation (PRL) on menstural cycle

Answer 7

• Inhibit ovulation = (temporary) Infertility
• therefore no menses =amenorrhea

Question 8

excessive prolactin in males causes

Answer 8

sterility

Question 9

factors causing Variations in PRL plasma levels

Answer 9

• Sleep: rises during sleep then plateaus when waking up
• Pregnency: rises gradully and reaches maximum during partrurition
• Suckling: produces sharp rises in prolactin (gradullay decreases after the first 3 months
• Stress: increases secretion

Question 10

effect of stimulating nipple in non-pregnent females on PRL plasma levels

Answer 10

Mild increase by the stimulus

Question 11

Prolactin inhibiting hormone is also known as ____

Answer 11

Dopamine

Question 12

Explain indirect negative feedback mechanism of Prolactin secretion

Answer 12

1. Prolactin secretion facilitates dopamine secretion from hypothalamus
2. this then reduced prolactin secretion

Question 13

Medications used in hyperprolactinemia

Answer 13

Dopamine agonists= bromocriptine

Question 14

Medications used in hypoprolactinemia

Answer 14

Dopamine receptor blockers= Chlorpromazine

Question 15

main cause of hyperprolactinemia

Answer 15

Adenoma

Question 16

Effect of hyperprolactinemia in females

Answer 16

• amenorrhea (absence of mensturation)
• galactorrhea during non lactation periods

Question 17

Effect of hyperprolactinemia in males

Answer 17

may produce sterility

Question 18

Effect of hyperprolactinemia in both sexes

Answer 18

Decrease Libido

Question 19

Sheehan syndrome in females is caused by ____

Answer 19

severe postpartum hemorrhage

Question 20

other names for Panhypopituitarism

Answer 20

• Simmond’s disease
• Sheehan’s syndrome (in females after sever pph)

Question 21

cause of Panhypopituitarism

Answer 21

Atrophy of all pituitary gland cells

Question 22

effect of Panhypopituitarism

Answer 22

No GH,thyroid, Suprarenal, gonadal, prolactin
* Decreased GH function:
- progeria (premature greying of hair)
- severe decrease in bodyweight (emaciation)
- Dry wrinkled skin
- Shrunken hands & feet
* Decreased thyroid function: decrease BEE + anemia
* Decreased cortical functions:
- Hypoglycemia
- Hypotention
- weakness
* Decreased Gondatrophic function: amenorrhea & Sterility