Normal Growth and Clinical Aspects

Question 1

what is another name for somatotrophin

Answer 1

growth hormone

Question 2

what is another name for somatostatin

Answer 2

growth hormone–inhibiting hormone

Question 3

what is somatomedian also known as

Answer 3

IGF-1 (as it mediates growth)

Question 4

where is growth hormone released from

Answer 4

the anterior pituitary

Question 5

what type of hormone is growth hormone

Answer 5

peptide hormone

Question 6

why is it not possible to use GH from animals to treat disease in humans

Answer 6

GH is species specific

Question 7

GH will only stimulate growth under the permissive action of which two hormones

Answer 7

thyroid hormones

insulin

Question 8

why do children with untreated hypothyroidism or poorly controlled diabetes have stunted growth despite having normal GH levels

Answer 8

as GH requires thyroid hormones or insulin to stimulate growth

Question 9

GH achieves its effects on cell division by an intermediate, what is this intermediate called

Answer 9

IGF-I (insulin-like growth factor-I)

Question 10

what secretes IGF-I

Answer 10

liver

Question 11

what is GH effect on bone

Answer 11

GH stimulates chondrocyte precursor cells in the epiphyseal plates to differentiate into chondrocytes

Question 12

once GH hormone has stimulated chondrocyte precursor cells what do they begin to secrete

Answer 12

IGF-I

Question 13

what effect does IGF-I have on differentiating chondrocytes

Answer 13

stimulates differentiating chondrocytes to undergo cell division and produce cartilage (the foundation for bone growth)

Question 14

what causes the epiphyseal plates to close during adolescence

Answer 14

plates close under the influence of sex steroid hormones

Question 15

what are the “direct” effects of GH

Answer 15

increases gluconeogenesis by the liver

Reduces the ability of insulin to stimulate glucose uptake by muscle and adipose tissue

Makes adipocytes more sensitive to lipolytic stimuli.

increases muscle, liver and adipose tissue amino acid uptake and protein synthesis

Question 16

what effect does insulin have on protein synthesis

Answer 16

increases protein synthesis

Question 17

what effect does insulin have on aa acid uptake

Answer 17

increases amino acid uptake

Question 18

what effect does insulin have on glucose uptake

Answer 18

increases glucose uptake

Question 19

what effect does GH have on protein synthesis

Answer 19

increases protein synthesis

Question 20

what effect does GH have on aa acid uptake

Answer 20

GH increases aa acid uptake

Question 21

what is GHRH

Answer 21

growth hormone releasing hormone

Question 22

what is basal [GH] in plasma

Answer 22

0-3ng/ml (in children and adults)

Question 23

what is the 24 hour mean of basal [GH] in plasma in adults

Answer 23

2-4ng/ml

Question 24

what is the 24 hour mean of basal [GH] in plasma in children

Answer 24

5-8ng/ml

Question 25

what type of hormones are GH and IGF-I

Answer 25

peptide

Question 26

how are GH and IGF-I transported in the blood

Answer 26

they are transported in the blood with a binding protein

Question 27

what percentage of GH is in the bound form

Answer 27

50%

Question 28

what are stimuli that increase GHIH (a.ka somatostatin)

Answer 28

glucose cortisol FFA REM sleep

Question 29

in the foetal period and the first few months of life what factor largely controls growth

Answer 29

nutritional intake

Question 30

after the first 8 months of life what hormone becomes a predominant influence on the rate at which children grow

Answer 30

GH

Question 31

what are stimuli that increase GHRH secretion (increase GH)

Answer 31

1. actual or potential decrease in energy supply to cells 2. increased AA in the plasma 3. stressful stimuli 4. delta sleep (growth during sleep , repair in adults) 5. oestrogens and androgens

Question 32

what is the importance of growth hormone during foetal life

Answer 32

minor, babies born deficient in GH and IGF-1 are of normal size

Question 33

how important is thyroid hormone in utero and childhood

Answer 33

essential particular in development of the nervous system

Question 34

what is cretinism

Answer 34

children are BORN hypothyroid, they have retarded growth because they have loss of TH permissive action on GH

Question 35

what will be GH levels in a person who has cretinism

Answer 35

GH levels are normal

Question 36

what is giantism

Answer 36

excess GH due to a pituitary tumour BEFORE epiphyseal plates close

Question 37

what is acromegaly

Answer 37

excess GH due to a pituitary tumour AFTER epiphyseal plates close