Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Hormonal & Reproductive Week 1 - WLB > Growth Hormone - Trachte > Flashcards

Growth Hormone - Trachte Flashcards

1
Q

What type of hormone is growth hormone?

A

Sommatotropic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of hormone is prolactin?

A

Mammotropic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What kind of receptor does Growth hormone act on?

A

Cytokine receptor (with tyrosine kinase) that activates JAK/STAT secondary messenger signal transduction pathway

(Hormone binding causes dimerization and internalization of complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is stimulatory for GH release?

A

Hypothalamus => Growth Hormone Releasing Hormone (GHRH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the target cells for Growth Hormone?

A

Several receptor isoforms of GHR expressed in nearly all cells

Liver produces Insulin-like growth factor-1 (IGF-1 = somatomedin)

IGF-1 has impressive similarity to insulin in structure

GH and IGF-1 are final hormones mediating GH Axis effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the direct effects of Growth Hormone?

Hint: 6 things

A

Na retention

Decreased insulin sensitivity

Lipolysis

Protein synthesis

Epiphysial growth

IGF-1 production by the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the indirect effects of Growth Hormone via IGF-1?

Hint: 4 things

A

Insulin-like activity

Anti-lipolytic activity

Protein synthesis

Epiphysial growth

***IGF-1 > GH stimulates chondrogenesis (growth) at epiphyseal growth plates in children.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What additional effects does Growth Hormone have on protein metabolism?

A

Increases amino acid uptake and protein synthesis

Retention of nitrogen, phosphorous and potassium

Abuse by athletes to increase muscle mass and athletic performance

Proposed for elderly to increase muscle mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What additional effects does Growth Hormone have on mineral metabolism?

A

Increases mineral density in bones after longitudinal growth ceases and epiphyses have closed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What additional effects does Growth Hormone have on carbohydrate metabolism?

A

Carbohydrate utilization is uniformly decreased

Hyperglycemia- diabetogenic

  • reduces tissue uptake of glucose
  • increases liver production of glucose
  • secondary insulin release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What additional effects does Growth Hormone have on fat metabolism?

A

increased mobilization of fats for energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When (day/night) does Growth Hormone typically get released?

A

Primarily at night.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What if you have no production of Growth Hormone?

A

No production of IGF-1

No inhibition of GHRH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the control pathway for Growth Hormone?

A

GHRH (hypothalamus) => increase GH production in pituitary

Somatostatin (hypothalamus) => decrease growth hormone production in anterior pituitary

GH => negative feedback on GHRH / increase IGF-1 production in liver

IGF-1 => negative feed back on GH and GHRH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What conditions occur due to a severe GH deficiency in children?

A

Proportional dwarfism

Laron syndrome (insensitive to GH => resistant to cancer and diabetes)

Turner’s syndrome (XO or XX with missing parts of one chroms.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What conditions occur with GH deficiency in adults?

A

generalized obesity

reduced muscle mass

asthenia (reduced energy, weakness)

reduced cardiac output

17
Q

Why is it not useful to assess for GH deficiency by testing random serum samples for hyposecretion?

A

due to pulsatile pattern of GH release

18
Q

How does the Insulin Tolerance Test assess for GH deficiency?

A

Administration of insulin to induce hypoglycemia which should stimulate the adrenal glands to secrete cortisol and the pituitary gland to secrete growth hormone.

Failure to respond to insulin may suggest the need for glucocorticoid and growth hormone replacement.

19
Q

What is the drug used as a GHRH analog for the arginine co-stimulation test?

A

SERMORELIN is a GHRH1-29 analog

20
Q

How does the Arginine/GHRH protocol to induce GH response?

A

Procedure:

  1. Baseline growth hormone and somatomedin-C (IGF1)levels.
  2. Inject 0.5 g/kg Arginine over 30 minutes intravenously.
  3. Inject 1 mcg GHRH over 1 minute intravenously.
  4. Serum growth hormone levels at 15, 30, 45, 60 minutes

Interpretation:
A growth hormone level greater than 8 ng/ml is a normal response.
A growth hormone level less than 8 ng/ml is an abnormal response suggesting growth hormone deficiency.

21
Q

What is the recombinant human growth hormone used to treat GH deficiencies?

A

Somatropin

22
Q

What is the goal in therapeutic treatment of GH hyposecretion syndromes like hypopituitarism, idiopathic short stature, Turner Syndrome growth deficiency, SHOX mutations, or trauma in children?

A

promote growth by:

give GH to maintain IGF-I levels in the mid-normal range for age- and gender-matched controls

23
Q

What is an early sign of hypopituitarism?

A

hypoglycemia is an early sign

=> due to unopposed action of insulin

24
Q

What things do you monitor in patients at 1- to 2-month intervals during recombinant human GH (rhGH) dose titration and semiannually to annually thereafter?

A

IGF-I levels

children: growth
adults: lipid profile, fasting glucose, bone density

25
Q

What are the potential negative side effects or rhGH therapy?

A

Antibodies to GH in 30% (usually of little consequence)

Scoliosis during rapid growth

Diabetogenic => Can see an impaired glucose tolerance test, ketosis/severe acidosis in diabetics (may require an increase in insulin)

Cortisol or hypothyroidism may inhibit growth following GH therapy

26
Q

Recombinant human IGF for IGF deficiencies not responsive to GH is used to treat which syndrome?

A

Laron-type dwarfism

  • Autosomal recessive
  • GH receptor variant which has weak binding to GH
  • Result is also low IGF-1 levels
  • Present at birth
27
Q

What are the two rhIGF treatments?

A
  1. Mecasermin (Increlex) = rh IGF-1
  2. Mecasermin rinfabate (Iplex) = contains a complex of recombinant human rhIGF-1 plus rh-insulin-like growth factor binding protein-3 (IGFBP3 = IGF carrier protein and hence modulates IGF effects)
28
Q

What are the potential adverse side effects of rhIGF treatments?

A

Hypoglycemia (administer immediately before or after a meal)

Liver effects: Increases cytochrome p450 - reduces the duration of drugs metabolized by that system - steroids, anticonvulsants

29
Q

What usually causes GH Hypersecretion?

A

Usually pituitary tumor (adenoma) of the somatotropes

30
Q

Hypersecretion of GH results in gigantism and/or acromegaly is determined by what?

A

determined by timing of epiphyseal plates closure

in children => gigantism (before growth plates close)

in adults => acromegaly (after growth plates close)

31
Q

What is different about the GH levels in acromegaly compared to normal GH levels?

A

GH levels in acromegaly do not show circadian rhythm or peaks and nadirs but are within normal range

(This makes it difficult to identify GH secretory excess)

32
Q

What receptors are targeted in potential medical treatments for hypersecretion of Growth Hormone or pituitary tumors?

A

Somatostatin (SSTRs analogs) and Dopamine (D2 agonists)

33
Q

What are the symptoms of acromegaly?

A

Lengthened jaw

Coarsened features

Growth in hands and feet

Stubby fingers

34
Q

How do you diagnose GH hypersecretion?

A
  1. An elevated IGF-1 is the first indication
  2. Confirmed by an elevated GH level 2hr after glucose administration (usually suppresses GH)
    - drinking 75 to 100 grams of glucose solution lowers blood GH levels to less than 1 (ng/ml) in normal individuals.
35
Q

What drug is a GH Receptor Antagonist that is an alternative and newer treatment for hypersecretion of GH?

A

Pegvisomant

36
Q

What is the MOA of Bromocriptine?

A

dopamine agonist

37
Q

What is the MOA of Octreotide?

A

long-acting somatostatin analog

Hormonal & Reproductive Week 1 - WLB (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions