AVP, oxytocin, growth hormones and pituitary

Question 1

What is the pituitary gland?

Answer 1

Integrates signals and releases hormones that regulate the functions of other endocrine glands.
Vital roles in homeostasis

Question 2

What is the two lobes the pituitary gland split into?

Answer 2

Anterior and posterior

Question 3

What is the driving force of the pituitary gland?

Answer 3

The hypothalamus

Question 4

Where is the pituitary gland located?

Answer 4

Base of the brain attached to the hypothalamus

Question 5

Anterior lobe of the pituitary gland

Answer 5

Synthesizes and secretes hormones in response to hypothalamic regulation.

Question 6

Posterior lobe of the pituitary gland

Answer 6

Stores and secrets hormones synthesized in the hypothalamus. (Does not produce any hormones)

Question 7

Does the posterior pituitary produce hormones?

Answer 7

No

Question 8

What two hormones are stored secreted by the posterior pituitary?

Answer 8

Antidiuretic hormones (ADH/vasopressin)
 Oxytocin

Question 9

What does antidiuretic hormone regulate (ADH/vasopressin)?

Answer 9

Regulation of renal failure

Question 10

What does oxytocin regulate?

Answer 10

Regulation of uterine contraction

Question 11

What the 4 things that feed into the hypothalamus that stimulate the posterior pituitary gland?

Answer 11

1. Hyperosmolarioty (main)
2. Angiotensin II (main)
3. Decreased atrial receptor firing
4. Sympathritric stimulation

Question 12

What two reports does ADH/vasopressin work on?

Answer 12

V1 and V2

Question 13

What does activation of the V1 receptor do?

Answer 13

Acts on the blood vessels casing constriction, increased systemic vascular resistance.

Question 14

What does activation of the V2 receptor do?

Answer 14

Kidneys, fluid reabsorption, increased blood volume

Question 15

What is the overall affect of vasopressin/ADH after activation V1 and V2?

Answer 15

Increased arterial pressure (increased BP). V2 regulates water excretion by decreasing, so retaining water.

Question 16

Effect of reduced ADH/vasopressin

Answer 16

Diabetes insipidus, copious hypotonic urine.

Question 17

Treatment for reduced ADH/vasopressin

Answer 17

V2 agonist - desmopressin (mimics vasopressin)

Question 18

Effect of excess ADH/vasopressin

Answer 18

Hyponatremia (diluted NA due to excess water)

Oedema

Question 19

Treatment for excess ADH/vasopressin

Answer 19

Demeclocycline (blocks transduction of V2)
Tolvaptan (V2 antagonist) (expensive)
Restrict fluids

Question 20

Cause of excess ADH/vasopressin

Answer 20

Tumor, head injury, TB

Question 21

ADH/vasopressin mechanism (5)

Answer 21

1. Hypothamalus stimulates posterior pituitary through hyperosmolarity and angiotensin, II
2. Vapsoresisibe secreted and acts of V1 and V2 receptor.
3. V1= blood vessel constriction = increased systemic vascular resistance
4. V2= Kidney fluid reapportion = increased blood volume (water retention)
5. Increased arterial pressure

Question 22

Oxytocin mechanism (3)

Answer 22

1. Stretch of uterus, uterine cervix and stimulation of breasts increases action potentials in axons of oxytocin-secreting neuron.
2. Action potential go to hypothalamus and simulation secretion of oxytocin via posterior pituitary
3. Oxytocin release increased uterine contraction and milk release from breasts.

Question 23

Clinical use of oxytocin (3)

Answer 23

Labour induction (Slow IV)
Prevention/treatment of hemorrhage (Prophylactic IM)
Labour too quick (Antagonist: Atosiban)

Question 24

Two types of hormones produced and secrete by anterior pituitary

Answer 24

Tropic and directly acting

Question 25

What do tropic pituitary hormones do?

Answer 25

Affect the section of other endocrine glands

Question 26

What do directly pituitary hormones do?

Answer 26

Act directly on pituitary glands

Question 27

Tropic pituitary hormones (3)

Answer 27

- Adrenocorticoid hormones (corticotrophin) - Follicle-stimulating hormone (FSH) and luteinising hormone (LH) - Thyrotropin (Thyroid stimulating hormone

Question 28

Directly pituitary hormones (2)

Answer 28

``` Growth hormone (somatropin) Prolactin ```

Question 29

Adrenocorticotropic hormone | (corticotropin) target

Answer 29

Adrenal glands

Question 30

``` Follicle-stimulating hormone (FSH) and luteinising hormone (LH) target ```

Answer 30

Reproductive system

Question 31

Thyrotropin (thyroid-stimulating | hormone) target

Answer 31

Thyroid gland

Question 32

Growth hormone (somatotropin) target

Answer 32

Liver, bone, muscles

Question 33

Prolactin target

Answer 33

Mammary glands

Question 34

Adrenocorticotropic hormone | (corticotropin) effect

Answer 34

Stimulate production of glucocorticoids, which regulate metabolism and stress response

Question 35

``` Follicle-stimulating hormone (FSH) and luteinising hormone (LH) effect ```

Answer 35

FSH stimulates maturation/production of sex cells LH stimulates sex hormones by the gonads

Question 36

Thyrotropin (thyroid-stimulating | hormone) effect

Answer 36

Stimulates the release of thyroid hormones which regulate metabolism

Question 37

Growth hormone (somatotropin) effect

Answer 37

Induce production of insulin-like growth factors, which stimulate body growth and higher metabolic rate

Question 38

Prolactin effect

Answer 38

Promotes milk production

Question 39

Adrenocorticotropic hormone | (corticotropin) RH/IH

Answer 39

Corticotropin-RH

Question 40

``` Follicle-stimulating hormone (FSH) and luteinising hormone (LH) RH/IH ```

Answer 40

Gonadotropic RH

Question 41

Thyrotropin (thyroid-stimulating | hormone) RH/IH

Answer 41

Thyrotropin-RH

Question 42

Growth hormone (somatotropin) RH/IH

Answer 42

Growth hormone-RH and Growth | hormone-IH (somatostatin)

Question 43

Prolactin RH/IH

Answer 43

Prolactin-RH and prolactin-IH | (dopamine)

Question 44

What are hypothalamic releasing factors?

Answer 44

Peptides Some regulate more than one hormone, and some hormones regulated by more than one releasing factor They also can on neurotransmitters in the CNS.

Question 45

Anterior pituitary hormone regulation mechanism general

Answer 45

1. Hypothalamus detects need for inhibition or increase of hormones and relapses RH/IH. 2. IH turns pituitary off 3. RH stimulates pituitary release of hormone to act on tissue which has an effect. 4. After desired effect, feedback to hypothalamus and pituitary to stop.

Question 46

When are high levels of growth hormone released? (4)

Answer 46

- Exercise - Sleep - Stress - Thyroid hormone enhanced secretion

Question 47

What is the growth hormone sensitive to?

Answer 47

Very sensitive to noradrenergic activation, beta-antagonist promotes secretion and alpha antagonist inhibit secretion.

Question 48

Two types of growth hormone deficiency

Answer 48

Secretion deficiency | Receptor defects

Question 49

Growth hormone secretion deficiency effects

Answer 49

Hypothalamic or pituitary dysfunction e.g. turners syndrome

Question 50

Growth hormone receptor defects effects

Answer 50

Laron type dwarfism; fail to produce IGF in response to GH

Question 51

Clinical manifestation of growth deficiency dependent on age

Answer 51

Children: growth retardation/dwarfism | Adult: increased body fat, decreased muscle and bone mass

Question 52

Treatment for dwarfism due to growth hormone section deficiency

Answer 52

Somatropin – SC injection strict guidelines for use and specialist initiation.

Question 53

What neurotransmitter can reduce growth hormone secretion?

Answer 53

Dopamine

Question 54

Growth hormone and glucose

Answer 54

Counter-regulates glucose: Hyperglycemia action Causes insulin resistance

Question 55

What neurotransmitter can reduce prolactin release?

Answer 55

Dopamine

Question 56

Hyperprolactinemia

Answer 56

Too much prolactin

Question 57

Treatment for hyperprolactinemia: Bromocriptine

Answer 57

Dopamine agonist | Reduces prolactin secretion

Question 58

Treatment for hyperprolactinemia: Cabergoline

Answer 58

Alternative dopamine agonist Less side effects Less data in pregnancy

Question 59

Treatment for hyperprolactinemia: Quinagolide

Answer 59

Non-ergot alkaloid