Endocrine, GH, thyroid

nelso418's version from 2017-03-17 10:29

Section 1

Question Answer
Nuclear receptorsmodulate transcription in target cells (ex: steroids, thyroid hormone, and Vit D)
membrane receptorsexert rapid effects on signal transduction pathways (ex: peptides and AA)
Primary diseaseimpaired function of the target endocrine gland (liver, bone, and other tissues)
Secondary diseaseimpairment of pituitary gland
Tertiary diseaseimpairment of hypothalamus delivery

Section 2

Question Answer
GHSomatropin - states of growth hormone deficiency - dwarfism
MecaserminIGF1 Agonist - Improves growth when GH deficient. Only used when GH isn't working properly on receptor
SermorelinGHRH analog - diagnostic test for GH secretion
Tesamorelinsynthetic analog of GHRH - used for HIV lipodystrophy
SomatostatinSRIH - acromegaly
OctreotideSRIH - IV, SC injection
LanreotideSRIH - Depot injection
SandostatinSRIH - IM monthly
PasireotideSRIH - IM monthly
PegvisomantGH receptor antagonist

Section 3

Question Answer
Vasopressin (ADH, AVP)anti-diuretic and vasopressor, Deficiency seen in diabetes insipidus
Desmopressin acetate (DDAVP)long acting synthetic analog of AVP - nocturnal enuresis, diabetes insipidus - more V2 activity
ConivaptanVasopressin Receptor Antagonist (IV) - cause excessive urination - used in HF, edema, etc.
TolvaptanVasopressin Receptor Antagonist (Oral) - cause excessive urination - used in HF, edema, etc.
OxytocinIV - induction of labor, IM - postpartum bleeding, Nasal - induce lactation
Estradiolcauses more release of OXT
Relaxininhibits release of OXT
AtosibanOxytocin antagonist - inhibits pre-term labor

Section 4

Question Answer
T4Tetraiodothyronine or thyroxine
Calcitoninregulate Ca metabolism
Iodide transporters into thyroid glandNa/I symporter, Pendrin
Na/I symporterinhibited by anions - thiocyanate, pertechnetate and perchlorate (anions)
Pendrin2nd transport enzyme at apical cell membrane
TPOThyrodial Peroxidase - Oxidizes Iodide to iodine, Iodinates tyrosine residues in thyroglobulin
TGBthyroglobulin - contains about 120 tyrosine moieties
Thioamide drugsblock TPO
TBGthroxine-binding globulin - how thyroid hormone is transported in blood
5'-deiodinase enzymeDeiodination of T4 -> T3
AmiodaroneClass 3 anti-arrythmic that blocks 5'-deiodinase


Question Answer
LevothyroxineT4 - treatment of choice for Hypothyroidism, increase dose in pregnancy
Armour, Nature-Throid, WesthroidDesiccated Thyroid - hog or beef thyroid glands
LiothyronineT3 - Myxoedema coma - used when rapid onset is required. AVOID in CVD
LiotrixMixture of T4 and T3 in 4:1 ratio - no advantage and costs more
Thioamidespotent inhibitors of TPO, ADR - agranulocytosis
Propylthiouracil (PTU)Thioamide - preferred in 1st trimester due to ptn binding, severe fatal liver injury may occur
Methimazole (MMI)Thioamide - used more frequently because doesn't have the BBW PTU has
Anion InhibitorsBlock uptake of iodide - competitive inhibition of transport mechanism (Na/I symporter)
Perchlorate, Pertechnetate, ThiocyanateAnion inhibitors - rarely used d/t aplastic anemia
Iodidesinhibit TPO reversibly - not very effective but used Pre-Op and in thyroid storm - AVOID in pregnancy
Radioactive Iodine>21 years. 131I the only isotope - easy administration

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