Regulation of Growth

Question 1

During what periods of life do your 2 growth spurts occur?

Answer 1

Postnatal

Pubertal

Question 2

GH/IGF-1, TH and steroids regulate what general changes in the body?

Answer 2

Growth and maturation

Question 3

Thyroid deficiency leads to abnormal what in cretinism (congenital hypothyroidism)?

Answer 3

Abnormal growth and development

Question 4

During what growth spurt does GH peak?

Answer 4

Puberty

Question 5

What is the relationship between GH and IGF-1 at puberty?

Answer 5

Parallel each other

Question 6

Decreased/constant levels in adulthood maintain what?

Answer 6

Lean body mass

Question 7

Will GH levels remain constant, increase or decrease during senescence?

Answer 7

Remain constant

Question 8

GH release increases in what 3 scenarios leading to pulsatile release?

Answer 8

↑ after exercise
With food restriction
During sleep

Question 9

What hormone is responsible for GH release?

Answer 9

GHRH

Question 10

What hormone is responsible for inhibiting GH?

Answer 10

GHIH (somatostatin)

Question 11

Gs targets what in the following pathway?

Gs → X → PKA → CREB signaling → PIT1 → GH/GH receptor regulation→ growth and development

Answer 11

Adenylyl cyclase

Question 12

What pairing of hormones will promotes long bone growth until closing of the epiphyseal plate?

Answer 12

GH & IGF-1

Question 13

What class of hormones will signal to close the epiphyseal plate at the end of puberty?

Answer 13

Sex steroids

Question 14

Is the following a direct or indirect pathway of growth?

Stimulation of liver → IGF-1 (somatomedin) → ↑ protein synthesis, cell division, & bone growth

Answer 14

Indirect

Question 15

Why is IGF-1 a better measurement of GH release vs measuring GH levels?

Answer 15

IGF-1 w/ longer half life

Question 16

Is the following a direct or indirect pathway of growth?

binding to receptors in tissue → intermediary fuel metabolism/ metabolic actions (unrelated to growth) → ↑ fat breakdown and glucose output by liver & ↓ glucose uptake by muscles

Answer 16

Direct

Question 17

↑ GH & IGF-1 will have what effect on? GHRH

Answer 17

↑ GH & IGF-1 → negative feedback on GHRH (↑ GHIH)

Question 18

Is GH release constant or situation dependent?

Answer 18

Situation dependent

Question 19

↑ dietary protein leads to what effect on GH, IGF, and insulin?
What impact does this have on growth and caloric storage?

Answer 19

↑ GH/ IGF/ insulin

↑ protein anabolism/ growth

Little to NO change in caloric storage

Question 20

↑ dietary carbs (hyperglycemia) leads to what effect on GH, IGF, and insulin?

What impact does this have on growth and caloric storage?

Answer 20

↓ GH
no change in IGF
↑ insulin

NO change in protein synthesis or growth

↑ caloric/ CHO storage

Question 21

In a caloric deficiency you have high GH, but no growth. Why is this?

Answer 21

↓ ICGF-1 → ↓ protein anabolism, growth

Question 22

What is X?

↑ GH & cortisol → ↑X → ↓ IGF-1 bioavailability to tissues → diverts GH → no growth (instead caloric mobilization)

Answer 22

IGF-BP3

Question 23

Does hyperglycemia result in increased or decreased GH?

Answer 23

Decreased

Question 24

Hypoglycemia → ↑ GH, ↓ insulin leads to what three caloric mobilization processes?

Answer 24

1. ↑ lipolysis
2. ↑gluconeogenesis
3. ↓ peripheral glucose uptake

Question 25

Low or high levels of cortisol have what effect on GH?

Answer 25

decreased GH secretion

Question 26

What impact will a normal/ median range of cortisol production have on GH?

Answer 26

Steady GH secretion

Question 27

T and GH in the liver enhance the secretion of what hormone?

Answer 27

IGF-1

Question 28

Does T or E have more growth effects?

Answer 28

T

Question 29

Will E (in the liver) increased or reduce IGF-1 secretions?

Answer 29

Reduce

Question 30

IN the absence of TH, will GH be able to produce growth?

Answer 30

No

Question 31

T or F: TH has an indirect effect on GH?

Answer 31

Indirect

Question 32

The following are the effects of what hormone? 1. ↑ metabolic needs prior to tissue accumulation 2. Facilitates linear growth of bone 3. Tooth development & eruption 4. Growth/maturation of epidermis, hair follicles, nails, alteres subQ tissues 5. Prolactin secretion and mammary gland development

Answer 32

Thyroid hormone

Question 33

What hormones increases cartilage chondrocyte activity in the growth plate and accelerates bone turnover

Answer 33

Thyroid hormone

Question 34

Thyroid receptors in the the osteoblasts stimulate bone remodeling via what

Answer 34

GF’s IL6/ PGE2 and IGF1 receptor

Question 35

Does exercise increase glucose uptake in the cells with or without insulin present?

Answer 35

Without

Question 36

insulin and diet facilitate muscle protein synthesis via what signaling pathway?

Answer 36

MTORC-1

Question 37

What inhibits MTORC-1? (3)

Answer 37

Myostatin Glucocorticoids Cytokines

Question 38

A deficiency in myostatin will lead to what with regard to the muscles?

Answer 38

Hypertrophy

Question 39

Will increased protein intake w'o conditioning/training lead to muscle synthesis?

Answer 39

Yes

Question 40

↑ linear growth due to excessive stimulation of GH at epiphyseal plate will lead to what disease?

Answer 40

Gigantism

Question 41

Chronic excess GH in the absence of linear bone growth is what disease?

Answer 41

Acromegaly

Question 42

Bone/ST deformities, enlarged hands and feet, thick skin, ↑ protein, ↓ body fat, vision changes, HA, hyperglycemia/DM are sx of what disease?

Answer 42

Acromegaly

Question 43

What imaging study will be used to dx a somatotrop adenoma resulting in acromegaly

Answer 43

Pituitary MRI

Question 44

↑ IGF-1, OGTT > 1 ng/mL is dx for what disease?

Answer 44

Acromegaly

Question 45

A GH deficiency will lead to what disease?

Answer 45

Dwarfism

Question 46

If pt becomes GH deficient in adulthood what are the effects?

Answer 46

Asx OR ↓ skeletal muscle mass/ bone density, ↑ HF risk, old age sxs

Question 47

Lack of GHRH, pituitary insufficiency, tissues unresponsive to GH, IGF-1 deficit, failure to produce IGF-BP3 will lead to GH excess or Gh deficiency?

Answer 47

GH deficiency

Question 48

With Laron dwarfism what receptor is deficient?

Answer 48

GH receptor

Question 49

The Pygmies of Cameroon have a deficit of what hormone?

Answer 49

IGF-1 deficit