Lecture 3

Question 1

What is growth hormone also knonw as?

Answer 1

Somatotropin

Question 2

What is the function of growth hormone?

Answer 2

Stimulates growth and influences metabolism

Question 3

Two effects growth hormone has on soft tissues?

Answer 3

Hyperplasia

• increase number of cells, Increase mitosis, Decrease apoptosis

Hypertrophy

• Increase size of cells, increase protein synthesis, increase a.a. uptake from blood (like insulin) –> both drive aa from blood into the tissues

Question 4

Two effects of GH on Bones

Answer 4

Increase length (epiphysis) chondrocyte division in growth plate

Increase thickness - periosteum

Question 5

Growth effects are not directly produced by GH, what do they use instead?

Answer 5

Use peptide mediators called, somatomedins

• insulin-like growth factors, IGF-1 & IGF-2

Question 6

What is responsible of the release of IGF-1 into blood?

Answer 6

Liver releases IGF-1 into blood when stimulated by GH

Question 7

What is the metabolic effect of GH on blood glucose?

Answer 7

Increase blood glucose by decrease glucose uptake by muscles - saving glucose for brain

Question 8

Metabolic effects of GH on fat?

Answer 8

Increases lipolysis (fat breakdown)

Question 9

What is the overall metabolic effect of GH on Glucose and Fat?

Answer 9

Muscles use fatty acids, not glucose as energy source

Question 10

What is responsible for the stimulation of GH release?

Answer 10

Stimulated by GHRH from hypothalamus

Question 11

What inhibits release of GH?

Answer 11

GHIH (somatostatin) from hypothalamus

Question 12

What is hypoglycaemia?

Answer 12

Low blood glucose

Question 13

What effect does stress, exercise, and hypoglycaemia have on GH release?

Answer 13

Increases GH release

Question 14

What is gigantism and what causes it?

Answer 14

Excess GH secretion before growth plates in bone close

Caused by GH-secreting tumor, congenital problem, etc.

Question 15

What is acromegaly?

Answer 15

GH oversecretion after growth plates close

Height is normal, bones thicken

Question 16

What is often associated with acromegaly?

Answer 16

Diabetes mellitus

• GH causing hyperglycemia and insulin resistance

Question 17

4 GH conditions?

Answer 17

Gigantism

Acromegaly

Dwarfism

Hyposomatotropism

Question 18

What is Hyposomatotropism?

Answer 18

Decrease of GH inolder dogs which may lead to alopecia and hyperpigmentation

Question 19

What is an example of exogenous GH source in animals?

Answer 19

Recombinant bovine somatotropin

Question 20

What does rBST do?

Answer 20

Increases persistence of milk in order to increase milk yield

Question 21

When does the secretion of prolactin begin?

Answer 21

Begins at parturition

Question 22

What stimulates release of Prolactin?

Answer 22

Prolactin-releasing hormone (PRH) from hypothalamus

Question 23

What is responsible for the inhibition of prolactin?

Answer 23

Prolactin-inhibiting hormone (aka NT dopamine)

Question 24

What is the function of Prolactin?

Answer 24

Stimulates milk production (lactogenesis)

Question 25

Does exogenous prolactin increase milk yield?

Answer 25

No, prolactin is more concerned with beginning of milk

Question 26

What is ACTH derived from?

Answer 26

Pro-opiomelanocortin (POMC)

Question 27

What does ACTH stimulate?

Answer 27

Release of cortisol from the adrenal gland

Question 28

What is ACTH often used for in clinical scenarios?

Answer 28

Used to diagnose and differentiate adrenal conditions