Tx of GH and Prolactin Diseases Flashcards
What is Sermorelin used for?
Hypopituitary dwarfism caused at the hypothalamus level (lack of GHRH is the problem here) This is also the most common form of hypopituitary dwarfism. (SIR wants MORE Girls that are Hawt, Real Hawt …GHRH…)
What is mecasermin used for and how does it work?
Hyperpituitary dwarfism aka Laron syndrome. GH receptors are malfunctioning, so you have tons of GH not able to do its job. Mecasermin is a recombinant form of IGF-1 (it is combined with a IGF protein that increase its t1/2) (in Meca they give a Sermin In God’s Favor..IGF)
What is a really obvious therapy for hypopituitary dwarfism?
hGH (human growth hormone) 0.1mg/kg 3x/day
What is bromocriptine used to treat and how does it work?
Acromegaly and Prolactinomas. This DA agonist inhibits GH release in ~50% of patients, most of who have tumors secreting GH and PRL and express D2 DA receptors (remember DA also inhibits PRL) (I like to think this drug is taking a giant football BRO and shrinking him, which might as well be sending him to the CRYPTS, because now he can’t play football and that’s all he’s ever been able to do)
What does octreotide treat?
Acromegaly. This synthetic form of SST has a much longer t1/2 than organic SST. You give this as a once a month injection. (OCTopi in the TIDE have Super Sharp Tentacles..SST. I try).
What does pegvisomant treat and how does it work?
Acromegaly. GH antagonist. It is a modified GH analog that binds to the GH receptor and blocks the real GH from binding, preventing IGF-1 release. (PEG leg MAN would be a great name for an ANTAGONIST)
Other than GH, what other hormones does SST inhibit?
ACTH TSH Insulin Glucagon Vasoactive intestinal polypeptide (VIP)
Pasireotide. What does it do?
Acromegaly. SST analog that is also approved for the treatment of Cushing’s disease if taking out the pituitary adenoma doesn’t work (remember SST also inhibits ACTH) (I think that PASsing through the TIDE can also expose you to Super Sharp Tentacles. I’m really trying here)
Say you have too much PRL. What kind of signs will you see (in females and males)
Females: galactorrhea, amenorrhea, infertility, loss of libido, occasionally visual disturbances
Males: gynecomastia, erectile dysfunction, loss of libido, occasionally visual disturbances
(Remember that GnRH is suppressed with too much PRL..so then you don’t have any FSH or LH either leading to lack of testosterone and no ovulation etc etc)
How would you treat hyperprolactinemia?
DA agonists like bromocriptine or cabergoline, because DA inhibits PRL. These drugs can also shrink PRL releasing adenomas, but then you’ll be on the drug 4evah.
What is Desmopressin and what does it treat.
It is a ADH analog and treats central DI and von Willibrand disease. It acts on V2 receptors in the collecting duct to increase water reabsorption. (it also somehow releases vWF from endothelial cells, go figure)
Sooo how does GH work?
It increases linear growth and muscle mass primarily by stimulating the synthesis of insulin like growth factor 1 (IGF-1 aka somatodemin C) in the growth plate of cartilage and the liver. IGF-1 stimulates chondrocyte replication and matrix formation. GH also directly stimulates fat metabolism and gluconeogenesis in da livah.
How can GH cause hyperglycemia in diabetes mellitus patients?
GH favors the use of fat for energy, not sugars like glucose. In diabetes mellitus, GH can cause hyperglycemia since glucose will build up as fat is used to supply the body with energy.
How is the release of GH regulated
Growth hormones releasing hormone (GHRH) stimulates the release of GH from the anterior pituitary. Inhibited by somatostatin (SST), which is released by the hypothalamus, and by glucose
What kind of receptor does GHRH act on?
G(s) protein receptor on somatotroph causing the activation of adenylyl cyclase and the eventual activation of PKA. This causes synthesis and release of GH from the pituitary
