Growth Hormones

Question 1

Growth Hormone is aka…

Answer 1

Somatotrophin

Question 2

A growth hormone deficiency results in 5 things…?

Answer 2

decrease in lean body mass
decrease in muscle bulk
decrease in protein anabolism
decrease in lipolysis
impaired glucose tolerance

Question 3

Function of thyroid hormones?

Answer 3

Promote CNS development, enhance GH secretion

Question 4

Function of androgens?

Answer 4

accelerate linear growth (puberty growth spurt), increase muscle mass, promote epiphyseal closure

Question 5

Function of estrogens?

Answer 5

Decrease somatic growth

promote epiphyseal closure

Question 6

Role of glucocorticoids (ie, cortisol) in growth?

Answer 6

INHIBIT somatic growth

Question 7

Growth Hormone Binding Proteins: role?

Answer 7

Bind to GH
May dampen oscillations in serum GH levels associated with pulsatile GH secretion
Plasma half-life of GH could be prolonged by decreased renal clearance of bound GH.

Question 8

Direct actions of GH/somatotrophin in adipose tissue and muscle/liver.

Answer 8

Adipose tissue: lipolysis

Muscle and liver: opposes insulin (leads to increased BG levels)

Question 9

indirect actions of GH (acting via somatomedins): effect on skel growth? protein synthesis? cell proliferation?

Answer 9

increases skeletal growth, increases protein synthesis, increases cell proliferation

Question 10

Name three causes of abnormal/stunted growth related to GH.

Answer 10

Overall deficiency of GH
Failure to respond to GH via receptor or post-receptor defect
Congenital hypothyroidism. Also associated with mental retardation.

Question 11

Is GH species-specific?

Answer 11

YES: porcine/bovine derivatives are not effective in humans

Question 12

What led to cessation of use of cadaver GH as treatment?

Answer 12

concern for prion disease (Creutzfeldt-Jacob)

Question 13

Effect of GH on amino acid uptake? protein synthesis?

Answer 13

increases. also increases protein synthesis in tissues.

Question 14

effect of GH on DNA & RNA synthesis?

Answer 14

increases

Question 15

Effect of GH on lipolysis?

Answer 15

increases

Question 16

Effect of GH on blood glucose levels?

Answer 16

Initially has insulin-like action (decr serum BG levels). But overall, induces hyperglycemia.

Question 17

What 3 conditions will promote release of GH?

Answer 17

Hypoglycemia, Increased AAs in blood, deep sleep

Question 18

What 4 conditions will inhibit release of GH?

Answer 18

Somatostatin, primary hypothyroidism, hyperglycemia, high serum FFA levels.

Question 19

Somatomedins released by what?

Answer 19

Target tissue and LIVER in response to GH.

Question 20

Somatomedins are AKA…

Answer 20

IGF-1 and IGF-2.

Question 21

What is the effect of somatomedins?

Answer 21

Indirect actions of GH:
Skeletal growth
Protein synthesis
cell proliferation