Flashcards in Random Organ systems - endo Deck (105)
What is the function of CRH of HPA? clinical notes?
increase ACTH, MSH, Beta-endorphin
CRH is decreased in chronic exogenous steroid use
What is the function of Dopamine of HPA? clinical notes?
Dopamine antagonists (antipsychotics) can cause galactorrhea
What is the function of GnRH of HPA? clinical notes?
increase FSH & LH
regulated by prolactin;
Tonic GnRH suppresses HPA axis
Pulsatile GnRH leads to puberty & fertility
What is the function of Prolactin of HPA? clinical notes?
Pituitary prolactinoma leads to amenorrhea & osteoporosis
What is the function of somatostatin of HPA? clinical notes?
decrease GH & TSH
Analogs used to treat acromegaly
What is the function of TRH of HPA?
increase TSH & prolactin
Name the neuroendocrine glands controlled by the medulla
Posterior pituitary => ADH & OT
Adrenal medulla => catecholamines
Hypothalamus => releasing hormones
What increases or decreases cholesterol desmolase action to convert cholesterol to pregnenolone?
increases => ACTH
decreases => ketoconzale
WRT calcium homeostasis, an increase in pH will cause what Sx?
increase in pH leads to increase affinity of albumin (neg charge) to bind to Ca+ causing hypocalcemia symptoms of cramps, pain, paresthesias, carpopedal spasm
What endocrine signaling pathways use cAMP?
FSH; LH, ACTH, TSH
CRH, hCG, ADH (V2 receptor), MSH, PTH
calcitonin, GHRH, glucagon
What endocrine signaling pathways use cGMP?
ANP & NO (EDRF) => think vasodilators
What endocrine signaling pathways use IP3?
GnRH, Oxytocin, ADH (V1 receptor), TRH;
Histamine (H1-receptor), AT-II, Gastrin
What endocrine signaling pathways use steroid receptor (intracellular action)?
Vit D, Estrogen, Testosterone, T3/T4;
Cortisol, Aldosterone, Progesterone
What endocrine signaling pathways use intrinsic tyrosine kinase?
MAP kinase pathway => think growth factors
Insulin, IGF-1, FGF, PDGF, EGF
What endocrine signaling pathways use receptor associated tyrosine kinase?
JAK/STAT pathway => think acidophiles & cytokines
Prolactin, Immunomodulators, GH
IL-2, IL-6, IL-8, IFN
Steroid hormones are lipophilic & bound to SHBG. Describe the increase & decrease in SHBG in men & women
men=> increase SHBG lowers free testosterone causing gynecomastia
women=> increase SHBG is found in OCPs & pregnancy but free estrogen is unchanged;
decreased SHBG raises free testosterone leading to hirsutism
What does T3/T4 do to the heart?
increases B1 receptors leading to increased CO, HR, SV, contractility
What does T3/T4 do to the BMR?
increases BMR via increase in Na/K ATPase activity causing more O2 consumption, increased RR & body temp
What causes a decrease in TBG? increase in TBG?
pregnancy or OCP use along w/ estrogen
What converts T4 to T3 in the periphery?
What is the role peroxidase of thyroid hormones?
Peroxidase responsible for oxidation & organification of iodide; couples MIT & DIT
What is the Wolff chaikoff effect?
excess iodine temporarily inhibits thyroid peroxidase leading to decreased T3/T4 production
Differentiate the Rx used for hyperthyroidism
Propylthiourcil inhibits both peroxidase & 5'-deiodinase
Methimazole inhibits peroxidase only
Treatment for prolactinoma
DA agonists => bromocriptine or cabergoline
Tx for acromegaly
Try to resect
If not cured then octreotide (somatostatin analog) or pegvisomant (GH receptor antagonist)
Differentiate DI based on water restriction test
Central DI will show > 50% increase in urine osmolarity
Nephrogenic DI while show no change in urine osmolarity
Tx for central DI
Intranasal DDAVP & hydration
Tx for nephrogenic DI
HCTZ, indomethacin, amiloride;
What are secondary causes of Nephrogenic DI?
hypercalcemia; lithium, demeclocycline (ADH antagonist that is former antibiotic rarely used)