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60 Cards in this Set

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general steps in hormone synthesis
1. preprohormone synthesized in rER; 2. signal peptides cleaved--> prohormone transported to Golgi; 3. more cleavage in golgi and HORMONE then packaged in secretory granules
amine hormones
derivates of TYROSINE, include thyroid hormone, Epi, NE
active form of G protein?
ATP-bound to alpha subunit
how does caffeine work?
inhibits phosphodiesterase which degrades cAMP (get more cAMP)
IP3 signalling mech
hormone + R--> Gq --> PLC --> DAG and IP3 --> PKC
which hormones of anterior pituitary most homologous to TSH?
FSH, LH (identical alpah subunits)
"children" of POMC
ACTH, MSH, beta-lipotropin, beta-endorphin
which hormone of anterior pituitary most related to GH?
prolactin
what increases the pulsatile secretion of GH?
sleep, stress, puberty, starvation, exercise, hypoglycemia
what decreases GH secretion?
somatostatin, somatomedins, obesity, hyperglycemia, preggers
what does GH do in liver?
causes production of somatomedins (insulin-life growth factors)
4 direct actions of GH
1. dec'd glucose uptake into cells; 2. inc'd lipolysis; 3. inc'd protein synthesis in mm; 4. inc'd production of IGF
actions of GH via IGF
inc'd protein synthesis! In chondrocytes--> growth spurt; in mm-->inc'd lean body mass; inc'd organ size
how is prolactin secretion regulated?
tonic inhibition by dopamine (which is stimulated by PRL); TRH increases PRL secretion
4 actions of PRL
1. stim milk production; 2. stim breast development (w/estrogen); 3. inhibits ovulation via GnRH inhibition; 4. inhibits spermatogenesis
how treat PRL excess?
bromocriptine (DA agonists)
hormones of the posterior pituitary?
ADH (supraoptic hypothal), oxytocin (paraventricular hypothal)
what inhibits the iodide pump/trap in thyroid follicular epithelial cells?
thiocyanate and perchlorate anions
Wolff-Chaikoff effect?
high levels of I- inhibit I- pump
significance of propylthiouracil?
inhibits peroxidase enzyme (which first catalyzes oxidation of I- to I2..and then other steps); used for treatment of hyperthyroidism
what happens when TSh stimulates thyroid?
iodinated thyroglobulin is taken back into follicular cells, digested and T3, T4 released into circulation. Leftover MIT, DIT deiodinated by thyroid deiodinase
what happens to T3, T4 in circulation?
mostly bound to TBG (inc'd in preggers); peripherally, T4-->T3 or rT3
bone manifestation of thyroid deficiency?
bone age < chronologic age, b/c TH stimulates bone maturations
effect of TH on heart?
upregulates beta 1 R
effect of TH on O2 consumption?
increases b/c of upregulation of Na-K ATPase (which uses ATP..which comes from O2..kinda)
which part of adrenal cortex makes mineralocorticoids?
(outermost) zona glomerulosa (works on kidneys..which have glomeruli)
which part of adrenal cortex makes glucocorticoids?
(middle) zona fasciculata
which part of adrenal cortex makes androgens (DHEA, androstenedione)
(innermost) zona reticularis (b/c you should be really particularis of your sex partners)
effect of ACTH on adrenal cortex?
stimulates cholesterol desmolase thereby increasing steroid synthesis; also upregulates own R
control of aldosterone secretion?
tonically--ACTH; also Ang II stimulates aldosterone synthase (corticosterone--> aldosterone)
4 actions of glucocorticoids
1. stim gluconeogenesis; 2. anti inflamm; 3. immunosuppressive; 4. upregulate alpha 1 R on arterioles
how do glucocorticoids stimulate gluconeogenesis?
1. increase protein catabolism in mm (more aa available); 2)decrease glucose utilization and insulin sensitivty of fat; 3) increase lipolysis (more glycerol available)
how are glucocorticoids anti-inflammatory?
induce synthesis of lipocortin (inhibits PLA2); inhibit production of IL-2, thereby inhibit proliferation of T cells; inhibit relase of His and serotonin from mast cells, platelets
Name the dz: Increased ACTH, hypoglycemia, hyperpigmentation, ECF volume contraction
Addison's disease
how is secondary adrenocortical insufficiency different from Addison's?
no hyperpigmentation; no volume contraxn ,hyperKalemia, metab acidosis
Conn's syndrome leads to?
HTN, hypokalemia, metab alkalosis, dec'd renin
name the dz: decreased cortisol and aldosterone, increased adrenal androgens, virilization, suppression of gonad function
21 hydroxylase deficiency
name the dz: decreased androgen and glucocorticoid levels, increased aldosterone, hypoglycemia, lack of pubes
17 hydroxylase deficiency
3 major cell types and their main export in islets of Langerhans?
alpha--glucagon; beta--insulin; delta--somatostatin, gastrin
what do delta cells islets of Langerhans secrete?
somatostatin, gastrin
what stimulates glucagon release from alpha cells?
decreased blood glucose
3 actions of glucagon
1. increase blood glucose; 2. increase blood FA, ketoacids; 3. increase urea production
mechanism of insulin secretion?
glucose binds GLUT 2 on beta cell membrane--> depolarization of membrane--> Ca channel opens, influx --> insulin secretion
why get hyPOtension in uncontrolled DM?
high [glucose] exceeds Tm in kidney so urine is very sugary-->osmotic diuretic
what stimulates secretion of PTH?
dec'd Ca; mildly dec'd Mg (severe hypoMg inhibits PTH secretion!)
"goal" of PTH
increase calcium, decrease phosphate
4 actions of PTH
1. increase bone reabsorp.; 2 inhibit renal phosphate reabsorp.(PCT); 3. increase renal Ca reabsorp.; 4. stimulate production of active vit D
Albright's hereditary osteodystrophy
pseudohypoparathyroidism cause by defective Gs in kideny and bone-->end organ resistance to PTH
how does chronic renal failure lead to hypocalcemia?
increased GFR--> increased sr phosphate which complexes with Calcium, thereby decreasing free Ca; also decreased vit D
"goal" of vit D
increase calcium and phosphate in ECF for bone mineralization
Calcitonin: a) where b)stim'd by c)action
a)parafollicular thyroid cells; b) increased sr Ca; c) inhibit bone reabsorp.
what do Leydig cells make?
testosterone
why can't Leydig cells make glucocorticoids and mineralocorticoids?
no 21 beta hydroxylase or 11 beta hydroxylase
significance of 5 alpha reductase?
enzyme that converts testosterone to DHT, found in accessory sex organs like the prostate
significance of finasteride?
inhibits 5alpha reductase (can tx BPH)
FSH acts on Sertoli cells to?
stimulate production of inhibin which has negative feedback effect on FSH
what do theca cells make?
androgens which are converted to estrogens by aromatase in granulosa cells
2 causes of end organ ADH resistance
1. drugs (Li!!! Inhibits Gs); 2. severe hypercalcemia (inhibits AC)
which diuretics can also be used for treatment of acute mountain sickness?
carbonic anhydrase inhibitors like acetazolamide (metabolic acidosis to combat respiratory alkalosis)
why get HTN in 11beta hydroxylase deficiency?
the precursor that the enzyme would act on is a weak mineralocorticoid