Week 6 Review Q's Flashcards
Pharma of GH (1-35) Physio of GH (36-55) GH and Growth factors biochem (56-88) behavioral science 1 (89-107) behavioral science 2 (108-118) patho lab assessment of growth disorders (119-132)
Growth hormone is made up of how many amino acids?
191 (2 disulfide bonds connecting them)
How does GH mediate its effects?
via IGF-1
Which of the following does NOT increase GH production? a. exercise b. low fatty acids c. high protein meal d. high sugar in blood e. ghrelin
d. high sugar in blood (low blood sugar stimulates GH, it has an anti-insulin effect)
During sleep, when is GH the highest?
after 60-90 minutes of sleep (stage 3 of 4 of sleep)
Dopamine acts to increase GH release by acting on which receptor? a. alpha 1 b. alpha 2 c. beta 1 d. beta 2
d. beta 2
serotonin and adrenergic agonists (ex/clonidine) act to increase GH release by acting on which receptor? a. alpha 1 b. alpha 2 c. beta 1 d. beta 2
b. alpha 2 (adrenergic receptors)
Where is somatostatin found? What does it inhibit?
found in hypothalamus and pancreas; decreases insulin, glucagon, and growth hormone
Which inhibits the release of GH? a. IGF-1 b. somatostatin c. both d. neither
c. both
Which inhibits the synthesis of GH? a. IGF-1 b. somatostatin c. both d. neither
a. IGF-1
Which two of the following stages is GH likely to increase in? a. neonate b. childhood c. adolescence d. adults e. elderly
a. neonate & c. adolescence (around puberty)
Whats the half-life of GH? What metabolizes it?
20 minutes liver and kidney
short term GH uptake VERSUS long term GH uptake (how does each affect carb uptake?)
short term causes increase of glucose uptake, but long term causes decrease of glucose uptake
What mediates the actions of growth hormone?
IGF-1
How can you determine if a kid has insufficient GH?
- growth less than 4cm per year
- no response to agents that usually increase GH secretion (low response= less than 7 microliters)
- delayed bone age
Which of the following is an analog of Growth hormone-releasing hormone (GHRH)? a. Mecasermin b. Somatrem c. Somatropin d. Sermorelin
d. Sermorelin
Which of the following is made by adding methionine amino acid? a. Somatropin b. Somatrem c. both d. neither
b. Somatrem
Which of the following can be taken orally? a. Somatropin b. Somatrem c. both d. neither
d. neither
What is used to treat Laron Dwarfism? explain.
Mecasermin is used because it’s an IGF-1 analog. In Laron Dwarfism, the GH receptor is insensitive or not functioning, so we bypass it and directly give IGF-1.
Hexarelin is an analog of … made up of … amino acids
Hexarelin is an analog of ghrelin made up of 6 aa’s (can be given intranasally)
How do androgen and estrogens interfere with GH action?
they enhance epiphysis closure
How do glucocorticoids interfere with GH action?
because they’re catabolic hormones (increase protein degradation) and that goes against GH
Which of the following has the exact AA sequence as GH? a. Somatropin b. Somatrem c. both d. neither
a. Somatropin (GH aka Somatropin)
How does GH affect drug concentrations?
it increases Cytochrome P-450 activity, and this metabolizes the drugs and decreases their serum level
Octreotide is an analog of what? What does it inhibit?
its an analog of somatostatin, so it decreases insulin, glucagon, and GH
Cabergoline & Bromocriptin are analogs of
dopamine (used to treat acromegaly)
What drug blocks GH receptors?
Pegvisomant
T/F: Octreotide is given orally
false, it can be given subcutaneously
When (time of day) should you give GH or GH analogs? Why?
in the evening, to mimic body rhythms
What’s the relationship between dopamine analogs and GH?
dopamine stimulates GH secretion in normal people, but in patients with acromegaly, Cabergoline & Bromocriptin, (dopamine analogs) it decreases GH secretion
Which is used to treat Pancreatic cell tumors (VIPomas)? a. Somatropin b. Octreotide c. Cabergoline d. Hexarelin e. Pegvisomant
b. Octreotide (also to treat carcinoid tumor and GH excess)
What two drugs normalize IGF-I levels in 35% of patients?
Cabergoline & Bromocriptin
Which has a side effect of vomiting? explain the mechanism. a. Somatropin b. Octreotide c. Cabergoline d. Hexarelin e. Pegvisomant
c. Cabergoline (vomiting due to the activation of the chemoreceptor trigger zone)
Which has a side effect of H. pylori infections? a. Somatropin b. Octreotide c. Cabergoline d. Hexarelin e. Pegvisomant
b. Octreotide
Which drug is given once or twice a month via intramuscular methods?
Somatrem
Which drug has a side effect of gall bladder contractility?
Octreotide
T/F: GH mainly targets the liver
true, it does have receptors in many places in the body but the liver is where IGF-1 is secreted which mediates GH activities (GH receptor is enriched in the liver)
What is more, GH in free form or GH bound to its binding protein (GHBP)?
they’re equal
What stabilized IGF-1? For how long can it do this?
IGF-1/IGFBP/ALS complex works to stabilize IGF-1 for up to 12 hours
What do you measure when you want to evaluate GH in the body?
GH’s half-life is very short, so we measure IGF-1, which has a longer half-life and is stimulated by GH (IGF-1 is a good indicator of GH levels)
Explain how GH can lead to the burn out of pancreatic beta cells?
GH has an anti-insulin effect, so it reduces glucose uptake and it increases glucose output. This results in high glucose in the blood, and that triggers insulin release. Insulin is getting released more and more (GH acting against it) that the body becomes insulin INsensitive. So now more insulin is needed to make the same progress. beta cells work more and more until they burn out. Just like us in medical school.
What occurs to insulin if no GH is present?
lower insulin secretion
GH is anabolic for which of the following? a. carbs b. fats c. proteins
c. proteins
How can you remove the lipolytic effects of GH?
if you give insulin along with it (long term GH effect becomes ketogenic)
What type of energy do we use when we sleep? why?
GH is released during sleep and it shifts the metabolism towards lipolysis conserve carbs and proteins.
How does GH effect urea production?
it increases amino acid uptake and helps the body retain nitrogen, thus decreasing urea production
What is the Protein sparing effect?
(aka amino acid sparing) is the process by which the body derives energy from sources other than protein. Such sources can include fatty tissues, dietary fats and carbs.
How do high amounts of free fatty acids and hyperglycemia effect GH release?
decrease it
Explain how sex hormones affect GH release.
sex hormones increase GH release, however, very high levels of sex sterioids- like in pregnancy- inhibit GH stimulation and release
Why are those with pituitary dwarfism likely obese?
GH-induced lipolysis lost
What condition is characterized by high GH but no IGF-I production?
Laron syndrome (remember: Laron Dwarfism is treated with IGF-I analogs)
What is Simmonds disease?
form of hypopituitarism due to pituitary destruction.
give me at least 3 symptoms of Simmonds disease
- Hypoglycemia
- Increase percentage of fat
- Decrease percentage of protein
- Muscle weakness and exhaustion
- Increased risk of heart disease
Which results in increased brain weight? a. acromegaly b. giantism
a. acromegaly
Which results in higher susceptibility to infections? a. acromegaly b. giantism
b. giantism