final exam Flashcards
somatotropin
-growth hormone
-released by the anterior pituitary in response to ghrh produced by hypothalamus
-released at max during sleep
-decreases with age as well as decreasing lean muscle mass
-promotes cell proliferation and bone growth
- moa is directly acted at targets (except for some that work through somatomedins like igf1 and igf 2)
somatropin
-synthetic hgh
-produced using recombinant dna
-indicates dwarfism, turner syndrome, prader willi syndrome, and aids wasting syndrome
-daily doses
-“anti aging” hormone because it increases lean body mass, bone density and skin thickness and decrease adipose tissue (shit be sold on the black market to old bitches and athletes)
-short half life, but induces igf1 from liver which has gh action
-adv eff include increased risk of diabetes. do not use in pt with closed epiphyses, diabetic retinopathies, or fatsos with prader willi
-prodrug lonapegsomatropin(skytrofa) can be used pediatrically once weekly
whats the deal with laron syndrome
- dwarfism caused by an insensitivity to gh (mutation on gh receptor)
-therefore somatropin is ineffective
-exceptionally low levels of igf1 and igf3 - treatment has to be done by biosynthetic igf1
somatostatin
-ghih (gh inhibitor)
- isolated from the hypothalamus, it is found in neurons, intestine, stomach, and pancreas
-in pituitary it binds to receptors that suppress hp and tsh(thyroid stimulating). also inhibits insulin glucagon and gastrin
- indicates gigantism(kids) and acromegaly(post epiphyseal closure) and acrogigantism(mix of the two)
synthetic somatostatin analogs
-synthetic analogs like octreotide and lanreotide are longer than the endogenous somatostatin
-can aid in diarrhea associated with carcinoid tumors and esophageal varices
-adv eff abdominal pain, farts, puke, steatorrhea, gallstones (delayed gallbladder emptying)
Dopamine receptor agonists and hgh excess
-bromocriptine and cabergoline
-inibit gh
-indicate acromegaly and pituitary microadenomas
-important note is that dop actually increases ghrh and somatostatin so kinda depends
synthetic Gh receptor antagonists
-pegvisomant
- indicates acromegaly that is refractory to other modes of therapy
thyroid shit you should probably know
-t4 and t3
-t4 20x amount of t3
- t4 is less potent but has longer half life
- t3 is more rapid (3days) while t4(11 days)
-t4 is converted into active t3 by 5’monodeiodinase
-t3 binds to nuclear receptors and initiates transcription this causes high metabolic rate and o2 consumption, wide spectrum of effects
-hyper: nervousness weight loss poopin tachycardia insomnia goiter bulging eyes
-hypo: lazy wieght gain no poopin tired not hungry weak goiter
hyperthyroidism
-nervousness weight loss poopin tachycardia insomnia goiter bulging eyes
-mostly caused by graves, which is where thyroid stimulating immunoglobins work against tsh receptors
- goiter or solitary hyperfunctioning adenoma in thyroid or pituitary
-sequelae(caused by?) is increased metabolic rate and physiological functions
-thyroid storm can happen, this is basically when metabolism and physiological functions go berserk it can lead to heart failure
-thyroid storm can be prevented by suppressing thyroid function with anti thyroid drugs
-b blockers can be useful too
-can remove the thyroid surgically or by killing it with radioactive iodine(can lead to hypo)
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Methimazole vs PTU (thiamides
- these are both treatments for hyperthyroid that inhibit hormone synthesis
- methimazole is better due to longer half life, but methimazole can only be used during the first trimester of pregnancy because it has teratogenic effects
-ptu can cause hepatotoxicity and agranulocytosis, therefore ptu should be a last resort
-ptu blocks peripheral t4 from converting into t3
-thioamides are concentrated in the thyroid and inhibit the oxidative processes for iodination and condensation of iodotyrosines to form t3 and t4
iodide
-blocks hormone release to treat hyperthyroid
- inhibits iodination of tyrosines but only lasts a few days
- inhibits the release of thyroid hormones from thyroglobulin by mechanisms not known
-treats thyroid storm or prior to surgery because it decreases the vascularity of the thyroid
-adv effects include throat swelling, rashes, ulcerations due to oral administration
hypothyroidism
-caused by hashimotos which is autoimmune destruction of the gland
-high tsh=goiter
-can be caused by surgery, radioactive treatment, or lithium
-can be caused by diet iodine deficiency (goitrogen veggies) though this is rare because we have a lot of iodine in salt
-slows down metabolism can cause :
-cretinism (dwarfism and retardation) which is during fetal development caused by maternal hypothyroidism
-myxedema which is deficiency in adulthood
hypothyroidism treatment
-levothyroxine(t4) is preferrable to liothyronine(t3) or liotrix(combo)
-t4 is better tolerated and has a longer half life
-levo is dosed once daily and reaches steady state in 6-8 weeks
-levo toxicity is nervousness tachycardia weight loss and such
-desiccated thyroid extract from farm animals can be generic med
-drugs that induce cytP450 like phenytoin rifampin and phenobarbitol accelerate metabolism of thyroid hormones and decrease effectiveness
extracellular calcium sensing receptor(casr)
-enables tissues involved in ca homeostasis to monitor blood calcium
-these tissues are pth secreting parathyroid glands(big one), calcitonin secreting thyroid c cells, intestines, bone, kidney
-calcium flux is regulated by pth calcitonin and 1,25dihidroxyvitamin d3 whose renal synthesis is homeostatically regulated
pth(parathyroid hormone)
-acts directly on bone and kidney to increase ca influx into plasma
-indirectly increases ca absorption from gut by stimulating 1,25oh2d in the kidney increasing blood calcium
-inhibits renal tubular reabsorption of pi increasing excretion
hypoparathyroidism
-hypocalcemia basically leaves too much na which depolarizes too much causing muscle spasms. this is hypocalcemic tetany
-can be caused by digeorge syndrome(born wo it)
-can be caused by genetic mutations of casr where chief cells assume serum ca is elevated when its not leading to lower pth
-can be autoimmune where casr is targeted, activating it, lowering pth
-latrogenic cause can be accidental removal during thyroidectomy
-idiopathic cause can be failure of tissues to respond to pth
-treated with teriparatide(acts like pth v effective in removing tetany) or calcium plus calcitriol(standard treatment)
osteoporosis
-bone resoption exceeds depostion
- estrogen normally inhibits osteoclasts and enhances osteoblasts, deficiency will do the opposite (can be postmenopausal which is primary)
-hypercortisolism (secondary)can do this because it increases rankl but decreases osteoprotegerin thereby increasing osteroclastogenesis
-also renal disease can cause it its secondary
-most common bone disease
-loss of bone and its minerals
-more common in women(WHO CARES BRUH FUCK THIS CLASS)
-can be prevented with calcium and vit d
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bisphosphonates
-inhibit bone resorption to treat osteoporosis
-alendronate ibandronate risedronate and zoledronic acid
-preferred agents for postmenopausal osteoporosis
-moa biphosphonates decrease osteoclastic bone resorption through increasing ostroclastic apoptosis and inhibition of the cholesterol biosynthetic pathway
salmon calcitonin
-for osteoporosis in women who are at least 5 years postmenopausal
-reduces bone resorption less effective than biphosphonates, but causes relief of pain
rankl antibodies
-inhibit osteoclastogenesis to treat osteoperosis
selective estrogen receptor modulators
-treat osteoperosis duh inhibit osteoclasts
-estrogen replacement is effective but can increase risk of endometrial cancer breast cancer stroke and cardiovascular shit so it aint used too much no more
-raloxifene has estrogen like effects on bone and estrogen antagonist effects on breast and endometrial tissue
sclerostin (sost)
- in animals, if sost is inhibited by monoclonal antibodies osteoblasts fuck off and new bones form.
-sost is a glycoprotein secreted by osteocytes and chondrocytes that has antianabolic effects that inhibit osteoblasts
-mutations in sost genes can create high bone mass (sclerosteosis)
-binds to lrp5/6 and inhibits wnt signaling leading to decreased bone form
-sost is inhibited by pth and estrogen
-shit is increased by calcitonin
Denosumab(prolia amgen)
-this is a monoclonal antibody that targets rankl and inhibits octeoclastogensis
-this ones all good in postmenopausal osteoporosis
-subcutaneous administration every 6 months
-risk of infection and osteonecrosis in the jaw(should be a last resort)
-soluble osteoprotegerin and denosumab have been effective in cancer patients with hypercalcemia of malignancy (prostate )
-this is due to cancers secreting pth related protein which promotes rankl and inhibits osteoprotegerin (denosumab targets rankl and fakes being osteoprotegerin preventin pthrp induced osteoclastogenisis
romosozumab (evenity)
-monoclonal antibody that inhibits sost resulting in increased bone formation to aid in osteoporosis
-specifically for osteoporosis in postmenopausal women or a last resort for other patients
-subcutaneous injection whose anabolic effects wane after 12 monthly doses
-adv eff are stroke myocardial infarction and death