Growth Hormone

Question 1

What causes hypoglycemia?

Answer 1

sleep or exercise

Question 2

hypothalamus produces GHRH in response to ____

Answer 2

hypoglycemia

Question 3

What is stimulated by GHRH?

Answer 3

anterior pituitary releases GH

Question 4

What is stimulated by GH?

Answer 4

1. Liver: insulin-like growth factor 1 (IGF-1) or somatomedin C
2. Bone & cartilage: osteoblasts (bone growth), chondroblasts (cartilage growth)

Question 5

what is stimulated by IGF-1 or somatomedin C?

Answer 5

1. Muscle:
   - increase AA uptake, protein synthesis, fat utilization –> muscle synthesis
   - decrease protein breakdown, CHO breakdown –> decrease muscle breakdown
2. Bone & cartilage: osteoblasts (bone growth), chondroblasts (cartilage growth)

Question 6

high blood sugar causes…

Answer 6

hypothalamus & delta cells of pancreas to produce somatostatin

Question 7

somatostatin turns off…

Answer 7

GHRH
GH
TSH

Question 8

somatomedin C turns off…

Answer 8

GHRH and GH

Question 9

GH turns off ____

Answer 9

GHRH

Question 10

what increases GH secretion?

Answer 10

hypoglycemia –> GHRH

Question 11

somatostatin - insulin secretion is an example of ____ regulation

Answer 11

paracrine

delta cells-> somatostatin, inhibits secret’n of insulin + glucagon

Question 12

exercise would likely increase secretion of ____

Answer 12

GH

(causes hypoglycemia)

Question 13

What physiological changes (increase/decrease) to muscle protein synthesis, muscle carbohydrate utilization, and femur length would occur with an increase in somatomedin C (IGF-1) release from the liver?

Answer 13

1. Protein synthesis: increased
2. CHO utilization: decreased
3. Femur length: increased