Midterm 2 - Importance of Growth Hormone Flashcards

1
Q

where does GH originate from

A

cells of the anterior pituitary

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2
Q

what does GH promote

A

tissue and body growth in young animals

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3
Q

what does GH especially promote

A

longitudinal growth until skeleton is complete

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4
Q

what does GH mainly control in adults

A

metabolism

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5
Q

does GH stimulate growth in fetal life

A

no - IGF1 and 2

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6
Q

what does protein sequence differ a lot between

A

species (poor cross reactivity)

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7
Q

what regulates GH

A

GHRH and GHIH

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8
Q

what increases GH secretion

A

high aa and low glucose content in plasma
exercising and stress
sex steroids

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9
Q

why does GH increase during sleep

A

it follows a circadian pattern

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10
Q

what type of eating will increase GH

A

high protein diet
long fasting

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11
Q

what happens at puberty due to GH

A

burst of growth

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12
Q

what is IGF1 responsible for

A

negative feed back on GH secretion

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13
Q

does GH have a short or long half life

A

short (about 20 min)

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14
Q

what does GH affect

A

most cells in the body

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15
Q

what type of hormone is GH

A

anabolic - promotes synthesis of protein (like insulin)

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16
Q

while being anabolic, what else is GH

A

a catabolic hormone - conversely to insulin GH stimulates lipolysis and reduces lipogenesis in adipose tissue

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17
Q

what does lipolysis increase

A

fatty acid production

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18
Q

what does GH decrease

A

glucose utilization in most tissue… in turn increasing glucose concentration in blood

19
Q

what does GH do its indirect roles

A

via IGFs

20
Q

what does GH stimulate

A

synthesis of IGF1 and its binding proteins in the liver

21
Q

aside from GH stimulation, where are small amounts of IGFs produced

A

locally in muscle and adipose tissue

22
Q

what is IGF1

A

a polypeptide chain with a sequence similar in human, porcine, and bovine

23
Q

what is a main difference between GH and IGF1

A

IGF1 has a much longer half-life than GH due to being bound to carrier proteins

24
Q

how does IGFs act

A

via its own tyrosine kinase receptors

25
Q

what does IGF1 stimulate

A

chondrocytes
satellite cells
aa uptake and protein synthesis

26
Q

does GH have any major role in mammary gland development

A

no

27
Q

how are GH effects on milk production mainly mediated

A

via metabolism, and partitioning nutrients to mammary gland for milk synthesis

28
Q

what does insulin normally direct nutrients towards

A

lipogenesis in adipose tissue - GH has opposite effect

29
Q

what can boost milk production

A

Bovine GH (bST)

30
Q

how much can bovine GH boost milk production by

A

10 and 40% in early and late lactation

31
Q

is overproduction of GH common in animals

A

no - rare

32
Q

what is overproduction of GH called before puberty (before skeleton is formed)

A

gigantism - increased longitudinal growth

33
Q

what is overproduction of GH after puberty (no more longitudinal growth)

A

acromegaly, increased bone width and density, diabetes

34
Q

what can be the cause of GH overproduction in old dogs and cats

A

pituitary tumor

35
Q

what is the result of a lack of GH production

A

dwarfism

36
Q

what causes dwarfism

A

mostly genetic defects of GH or GH receptor genes

37
Q

how can dwarfism be treated

A

injection of recombinant GH and IGF1

38
Q

what happens to dogs with dwarfism

A

they keep their puppy coat for a long time due to lack of IGF1 action on hair follicle differentiation

39
Q

what does GHRH do

A

stimulates GH

40
Q

what does GHIH (somatostatin) do

A

inhibits GH

41
Q

what does GH do with IGF1

A

stimulates IGF1 production by liver –> IGF1 stimulates cartilage and bone growth and milk production

42
Q

what does GH regulate

A

lipid and protein metabolism

43
Q

what family is GH receptor a member of

A

the interleukin (cytokin) family