Drug Effects on the Hypothalamic Pituitary Axis Flashcards
Where is growth hormone release from?
the anterior pituitary
What stimulates the release of growth hormone?
growth hormone releasing hormone and ghrelin
What inhibits the release of growth hormone?
somatostatin
What is the action of growth hormone?
acts on the liver to stimulate the release of IGF-1
What is growth hormone insensitivity?
where the liver doesnt respond to growth hormone so no IGF-1 is released
What is a secondary deficiency of growth hormone?
where the pituitary doesnt produce growth hormone
What is a tertiary deficiency of growth hormone?
a lack of growth hormone releasing hormone and ghrelin so no growth hormone is released
Why isnt growth hormone orally bioavailable?
because its a peptide
Why do GHRH and ghrelin have a synergistic effect?
because GHRH receptor elevates cAMP and ghrelin receptor elevates calcium
What is the treatment for growth hormone insensitivity?
IGF-1
What treatments can be used to reduce growth hormone release?
somatostatin analogues, dopamine agonist
What treatments can be used to inhibit growth hormone action?
growth hormone antagonist (pegvisimat)
How does pegvisimat work?
pegvisimat is growth hormone that has been mutated so that only one of the two binding sites works so that it is able to bind the receptor but not activate it and is pegylated to give it a longer half life than growth hormone
What are the treatments for Grave’s disease?
radioactive iodide to ablate the thyroid gland, carbimazole to inhibit thyroid peroxidase, propylthiouracil to inhibit thyroid peroxidase and conversion of T4 to T3, surgical resection of the thyroid, thyroid arterial embolisation
What are the treatments for Hashimoto’s disease?
thyroxine (T4) or liothyroine (T3)
