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80 Cards in this Set
- Front
- Back
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what pituitary hormones activate JAK/STAT receptors
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GH and prolactin
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what pituitary hormones activate G protein-coupled receptors
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ACTH, TSH, FSH, and LH; all but ACTH share a common alpha chain
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what inhibits prolactin
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dopamine through D2 subtype of receptors
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what hormones or analogs of them are used frequently clinically
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GH, SST, LH, FSH, GnRH
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what hormones or analogs of them are not used frequently clinically
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TRH, TSH, CRH, ACTH, GHRH
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GH deficeincy in childhood results in
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short, increased body fat, decreased muscle mass
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half-life of endogenous GH
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20-25 minutes; cleared by liver
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how is recombinant GH given
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subcutaneously 3-7 times per week; peaks in 2-4 hours and persists ~36 hours
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where is most circulating IGF-1 produced
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liver
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why are effects of GH on carb metabolism mixed
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GH and IGF-1 have opposite effects on insulin sensitivity - GH reduces causing mild hyperinsulinemia
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early sign of GH deficiency
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hypoglycemia - unopposed affect of insulin
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asthenia
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reduced strength
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Prader-willi syndrome
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autosomal dominant; growth failure, obesity, carb intolerance; GH can be used as treatment
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cost of GH replacement in idiopathic cases
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35,000 per inch height gained
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side effects of GH treatment
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hypothyroidism, intracranial hypertension in children
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how does oxytocin differ from vasopressin
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2 amino acids in a 9 aa chain
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how is oxytocin eliminated
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kidneys and liver; half-life of 5 minutes
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receptors for oxytocin
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G protein and phosphoinositide-calcium second messenger for uterine smooth muscle
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what does oxytocin stimulate the release of that augments uterine contractions
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prostaglandins and leukotrienes
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beginning infusion rate of oxytocin for inducing labor
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0.5-2 mU/min increasing every 30-60 minutes until good pattern established; max rate of 20 mU/min
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atosiban
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oxytocin antagonist
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tocolysis
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preterm labor
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desmopressin acetate
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lon-acting synthetic analog of vasopressin; minimal V1 activity
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half-life of circulating vasopressin
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~15 minutes
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how can desmopressin be administered
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IV, subQ, intranasally, orally; half-life 1.3-2.5 hours
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what receptors does vasopressin activate
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G protein coupled; V1 on vascular smooth muscle (vasoconstriction) and V2 on renal tubule cells
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what do extrarenal V2 receptors do
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regulate release of coagulation fator VIII and von Willebrand factor
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vasopressin antagonists
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conivapran and tolvaptan; reduce hyponatremia and heart failure
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mecasermin use
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treatment of severe IGF-1 deficiency that is not responsive to GH
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mecasermin content
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rhIGF-1 plus rhIGFBP-3
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most important adverse effect of mecasermin
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hypoglycemia - should consume with meal
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what can small GH-secreting adenomas be treated with
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somatostatin analogs, dopamine receptor agonists, pegvisomant
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pegvisomant
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prevents GH from binding its receptor
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fxn of somatostatin endogenously
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inhibit release of GH, glucagon, insulin, gastrin
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exogenous somatostatin half-life
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1-3 minutes; rapidly cleared by kidneys
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why does somatostatin have limited usefulness clinically
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short half-life; multiple system involvement
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octreotide
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somatostatin analog; 45 times more potent at inhibiting GH release, only 2 times more potent in reducing insulin secretion; half-life 80 minutes
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octreotide alternative uses
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variety of hormone secreting tumors, diabetic diarrhea, acute bleeding in esophageal varices
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similar alternative to octreotide
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lanreotide
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how does pegvisomant work
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increased affinity for one site of GH receptor, but reduced affinity at its second binding site
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FSH in women
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direct ovarian follicle dvlp
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FSH and LH in steroidogensis in ovary
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LH stimulates theca cells to produce androgens in follicular stage; FSH stimulates granulosa cells to convert androgens to estrogens
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hCG
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placental protein nearly identical to LH; actions mediated via LH receptors
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FHS in men
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regulator of spermatogenesis; high local androgen concentrations via Sertoli cells
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LH in men
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testosterone production by Leydig cells
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menotropins
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human menopausal gonadotropins hMG; first commercial gonadotropin product; 4% potency
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three forms of purified FSH
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Urofollitropin (uFSH), follitropin alfa and beta (rFSH - recombinant) - only differ in carbohydrate side chains
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Lutropin alfa
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recombinant LH; only approved for women with profound LH deficiency
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Choriogonadotropin alfa (rhCG)
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recombinant hCG; subQ
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common causes of anovulation
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hypogonadotropic hypogonadism, polycycstic ovary syndrome, obesity, other
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ovulation induction general procedure
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after menstruation FSH begun and continued 7-12 days, hCG administered to induce follicular maturation and ovulation
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what does treatment in hypogonadal men require
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FSH and LH; treatment of 4-6 months required before sperm appear in ejaculate
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2 most serious complications of women treated with gonadotropins and hCG
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ovarian hyperstimulation syndrome and multiple pregnancies
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characteristics of ovarian hyperstimulation syndrome
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ovarian enlargement, ascites, hydrothorax, hypovolemia, shock; 0.5-4% of patients treated
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risk of multiple pregnancy with treatment
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15-20%; general population is 1%
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what is required to stimulate the gonadotroph cell to produce and release LH and FSH
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pulsatile GnRH secretion
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gonadorelin
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acetate salt of synthetic human GnRH
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synthetic analogs of GnRH
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goserelin, histrelin, leuprolide, nafarelin, triptorelin; all have D-amino acids; more potent and longer lasting than native GnRH
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half-life of gonadorelin
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4 minutes
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other uses of GnRH besides ovulation inducation
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prostate cancer
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how long after onset of puberty does it take for the hypothalamic-pituitary system to produce LH surge and ovulation
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several months to a year
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highest amplitude and frequencies of GnRH during menstrual cycle
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amplitude in luteal (favors FSH secretion), frequency in late follicular (favors LH secretion)
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biphasic response to exogenous GnRH and analogs
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stimulatory first 7-10 days, then inhibitory
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why is GnRH sometimes used in place of hCG for ovulation stimulation
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less likely to cause multiple ova and cause ovarian hyperstimulation syndrome
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what can differentiate btwn delayed puberty and hypogonadism
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single dose of GnRH, LH level recorded
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what is used to supress endogenous LH surge during controlled ovarian hyperstimulation for in-vitro
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subQ daily leuprolide or nasal nafarelin
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why is recommended duration of treatment of GnRH agonist limited to 6 months
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can result in decreased bone density; used for endometriosis
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uterine leiomyomata (fibroids)
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benign, estrogen sensitive, fibrous growths - cause menorrhagia, anemia, pelvic pain; treatment similar to endometriosis
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how can tumor flares be avoided in prostate cancer with GnRH agonist therapy
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administer bicalutamide or one of other androgen receptor antagonists
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4 synthetic decapeptides that fxn as GnRH receptor antagonists
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ganirelix, cetrorelix, abarelix, degarelix
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uses of GnRH antagonists
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controlled ovarian hyperstimulation, prostate cancer
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abarelix use
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advanced prostate cancer; dagarelix is similar
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signs and symptoms of androgen deprivation
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hot flashes, sweats, gynecomastia, decreased libido, decreased hematocrit, reduced bone density
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hyperprolactemia symptoms in women
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amenorrhea, galactorrhea
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hyperprolactemia symptoms in men
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loss of libido, infertility
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treatment for lack of prolactin
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none available
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dopamine agonists
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bromocriptine and cabergoline -ergot derivatives with high affinity for D2 receptors; quinagolide - D2 receptors
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what else are dopamine agaonists used for
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Parkinson's disease (ergot derivatives)
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cabergoline half-life
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65 hours
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why are dopamine agonists no longer used for women postpartum who don't wish to breast feed
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rare reports of stroke or coronary thrombosis
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