Endocrine Week 1 Flashcards
Are group I hormones lipophilic or hydrophilic?
Do they have transport proteins?
What is their half life like?
Lipophilic
Yes
Long
What hormones are in Group I?
Steroids, iodothyronines (thyroid)
List the following in order of longest to shortest half life: Steroids, thyroids, peptides/proteins
Thyroid>Steroids>Peptides/proteins
What is the rate limiting step for all steroidogenic pathways?
StAR protein mediation of cholesterol uptake from cytosol to inner mitochondrial membrane
What determines the major steroid product of each gland?
enzyme expression
What determines which circulating secretagogue the gland will respond to?
G-coupled protein receptor
Quick summary of the following types of signaling: A) Endocrine B) Paracrine C) Autocrine D) Neurotransmitter E)Neuroendocrine
A) cell to distant cell B) cell to adjacent cell C) cell to itself D) neuron to adjacent neurons E) neuroendocrine cell to distant organ
Where can thyroid hormone receptors be found?
Glucocorticoid receptors?
Peptides, etc?
Nuclear receptors
Cytoplasmic or Nuclear receptors
Cytoplasmic receptors
What differentiates polypeptide receptors from proteins?
Proteins have a tertiary structure
What enzyme is targeted in breast cancer? What are its actions?
Aromatase
Converts androstenedione to estrone (E1 which is then converted to E2/estradiol which promotes growth in estrogen related tumors)
Hypothalamus releases what hormone to the anterior pituitary? What hormone does the anterior pituitary release to the adrenal cortex? What does the adrenal cortex release that inhibits the previous two hormones?
CRH
ACTH
Cortisol
Example of positive feedback
Ovulation during menstrual cycle (estradiol leads to more hormone)
Childbirth (cervix stretch->post pit->uterine contraction->stretch)
Lactations (suckling->post pit->oxytocin->milk)
How do you recognize secondary hyperfunction?
Secondary hypofunction?
Cushing’s example: ACTH is inappropriately elevated when it should be suppressed by cortisol
Secondary adrenal insufficiency: ACTH is inappropriately unelevated in relation to the low levels of cortisol
Which portion of the pituitary is more cellular? Which is more fibrous and resembles nerve tissue?
Anterior pituitary (distal, intermediate, tuberal lobe) Posterior pituitary (neural lobe, pituitary stalk, median eminence)
What will damage to long portal vessels cause?
atrophy of anterior pituitary
Effects of pituitary adenoma?
Excess hormone secretion–endocrine syndromes
Can compress optic chiasm
Most thyroid tumors are derived from what type of cells?
follicle epithelial cells
Adipocytes are a constant feature of what gland?
Parathyroid
What disease do you think of when serum calcium levels are persistently low?
Primary hyperparathyroidism
What are the key characteristics of steroid secreting cells?
abundant smooth ER
tubulovesicular cristae in mitochondria
membrane bound lipid droplets
What germ layer are the endocrine and exocrine layers derived from?
epithelium
What is the pituitary gland derived from?
Oral ectoderm/hypophyseal diverticulum/Rathke’s Pouch
(forms anterior lobe, pars distalis & tuberalis & intermedia)
Neural ectoderm/Infundibulum
(forms stalk and posterior lobe)
Craniopharyngioma symptoms?
Originating tissue?
Optic chiasm impingement, hyrodephalus, pituitary dysfunction
Rathke’s pouch remnants-pharyngeal hypophysis
Aberrant thyroid tissue is found where most often?
What are midline structures that can rupture or form fistula?
Base of tongue
Thryoglossal Duct cysts
What do the parathyroid glands originate from?
Pharyngeal pouches 3 & 4
What does the initial wave of epithelial cells form? The second wave?
Fetal adrenal cortex
Definitive adrenal cortex
Neural crest forms secreting cells in which glands?
Thyroid, adrenal
Name the tissue these glands are derived from: Pituitary Thyroid Parathyroid Adrenal
Ectoderm
Endoderm
Endoderm
Mesoderm
What is the primary determinant of free water excretion in humans?
regulation of urinary water excretion by circulating levels of vasopressin
What is the major factor controlling AVP release?
plasma osmolality
The release of vasopressin is more sensitive to which:
changes in volume/pressure
osmoreceptor response
osmoreceptor response
Primary site of AVP response
collecting duct
Causes for SIADH
lung disease, drugs, cerebral
First step after noting hyponatremia?
measure serum and urine osmolality
Hypotonic serum, >100 mOsm/L in urine may be SIADH
What are conivaptan and talvaptan used for?
Vasopressin receptor antagonists for SIADH
What other drugs can be used for SIADH (not antagonists)?
furosemide, bumetanide
What must nephrogenic and central diabetes insipidus be distinguished from?
primary polydipsia
What to test with hypernatremia?
Volume status and urinary sodium content
euvolemia and variable sodium may be diabetes insipidus or dipsia
If you have polyuria, what test results indicate diabetes inspidus?
low urine osmolality (300)
If the the serum osmolality and sodium do not rise above normal and you suspect polydipsia, what will happen to urine osmolality?
concentrates
What is DDAVP?
synthetic ADH for central diabetes insipidus (desmopressin)
Structures in the cavernous sinus that could be compromised by pituitary growth
internal carotid artery
cranial nerves III, IV, V1, V2, VI
Two posterior pituitary nerves
ADH, oxytocin
Drugs that cause hyperprolactinemia
metoclopramide, risperidone
dopamine antagonists
Symptoms of hyperprolactinemia in patient
Typically women
menstrual irregularities, galactorrhea, infertility
Treatment of hyperprolactinemia
Dopamine agonists
cabergoline (preferred), bromocriptine
Methods to diagnose acromegaly
serum IGF-1
oral glucose tolerance test
Drugs to treat acromegaly
octreotide, lanreotide
cabergoline (works in limited population)
pegvisomant (GH receptor antagonist)
Drug treatment for GH deficiency in children
recombinant human growth hormone (rGH)
What is a condition that would alter the metabolism of cortisol?
chronic liver disease
What enzyme converts cortisol to the inactive cortisone?
11B-HSD2
In what areas of the body can cortisone be converted back to cortisol?
liver, visceral fat (by 11B-HSD1)
What substance is elevated in pts with 17-hydroxylase deficiency in order to compensate for lack of cortisol?
corticosterone
Drug used to treat endogenous hypercortisolism`
mifepristone (glucocorticoid receptor antagonist)
Organ deficient in:
A) primary adrenal insufficiency
B) secondary adrenal insufficiency
C) tertiary adrenal insufficiency
A) adrenal gland
B) pituitary gland
C) hypothalamus
Notable lab abnormality in primary adrenal insufficiency
hyponatremia
drugs that cause primary adrenal insufficiency
ketoconazole, etomidate, mitotane, mifepristone
A cause of false negatives in cosyntropin test of adrenal insufficiency
oral contraceptives
Drug that can cause isolated ACTH deficiency
ipilimumab
Drug used for primary and secondary adrenal insufficiency
hydrocortisone
Diagnoses that raise your suspicion for Cushing syndrome?
diabetes/hypertension/metabolic syndrome, osteoporosis, adrenal nodules
Will ACTH levels be low or high in ACTH independent Cushing’s?
low
Medical therapies for Cushing’s
Pasireotide (somatostatin receptor agonist)–pituitary directed
Metyrapone - 11-B hydroxylase inhibitor (adrenal steroid inhibitor)
Mifepristone: glucocorticoid and progesterone receptor inhibitor
