Principles of Endocrinology Flashcards
what hormones have the same alpha subunit (dimeric glycoprotein)
- FSH
- TSH
- LH
- human chorionic gonadotropin (hCG)
response time of the endocrine system
slow and long lasting (minutes to days)
response time of the nervous system
rapid and brief (msec)
response specificity of endocrine system
widespread responses with specific receptors on many targets
response specificity of nervous system
have precise local targets and enzymes stop the signal
what does the liver contribute endocrinologically
angiotensinogen and IGF-1
classes of hormones
- peptides/proteins
- catecholamines/indoleamines
- thyroid hormones
- steroids (and vitamin D)
what is the fate of hormones through the system
- once released, travels either bound or unbound via blood and binds (in its free state) to receptor in or on target cells.
then, unbound hormone degrades and is excreted via urine or bile or recycled.
solubility of peptides
water soluble
biosynthesis of peptides
made in prepro or pro hormone states, where the active form is not produced until it’s at the target
storage of peptides
substantial
binding proteins with peptides?
rare
half life of peptides
short (minutes)
peptide receptors location
plasma membrane
describe the steps of peptide synthesis
- DNA is transcribed in the nucleus.
- mRNA is translated in the ribosomes
- the preprohormones travel to the ER for cleavage.
- prohormones are modified in the golgi apparatus.
- hormone is placed in secretory vesicles for fast release.
what is the most common post-production modification done to peptide?
glycosylation
examples of hormones/peptides that are exocytosed?
Ach, GABA, oxytocin, dopamine, epinephrine, norepinephrine, histamine, serotonin, substance P, glutamate, glycine, NO
solubility of catecholamines/indoleamines
water soluble
biosynthesis of catecholamines
enzymatic pathway
storage of catecholamines?
substantial
binding proteins of catecholamines?
rare
half life of catecholamines
very short (seconds)
catecholamine receptor location
plasma membrane
what is serotonin
indoleamine
what is histamine
imidazoleamine
what is melatonin
indoleamine
what are the catecholamines?
epinephrine, norepinephrine, dopamine
solubility of thyroid hormones
lipid soluble
biosynthesis of thyroid hormones
enzymatic pathway
storage of thyroid hormones
substantial (in colloids)
binding proteins of thyroid hormones?
yes
half life of thyroid hormones
very long (days_
thyroid hormone receptor location
nucleus
where is calcitonin made?
parafollicular cells of the thyroid
where is T3 and T4 made
follicular cells of the thyroid
where is PTH made
chief cells of parathyroid gland
what is thyroglobulin
precursor to monoiodotyrosine (MIT) and diiodotyrosine (DIT)
what makes up T4
have 2 DIT
what makes up T3
have 1 DIT 1 MIT
what is the source of catecholamines and thyroid hormones?
tyrosine
solubility of steroids
lipid soluble
biosynthesis of steroids
enzymatic pathway
storage of steroids
minimal produced, so no storage
made PRN
binding proteins for steroids
yes
half life of steroids?
long (hours)
steroid receptor location
intracellular, nuclear
what receptor is associated with catecholamines/peptide hormones?
tyrosine kinase activity
which hormones use g protein coupled receptors?
ACTH FSH LH PTH TSH glucagon insulin epinephrine norepinephrine dopamine
what stops the cAMP cascade?
phosphodiesterase
what substances are associated with receptor tyrosine kinases ? (RTK)
growth factors or cytokines, then can activated multiple events after binding
what is signal amplification
some hormones are potent despite low plasma concentrations, so activate many enzyme molecules
mechanism of ACTH
adenyl cyclase mechanism (cAMP)
mechanism of LH
adenyl cyclase mechanism (cAMP)
mechanism of FSH
adenyl cyclase mechanism (cAMP)q
mechanism of TSH
adenyl cyclase mechanism (cAMP)
mechanism of ADH (V2 receptor in kidney)
adenyl cyclase mechanism (cAMP)
mechanism of MSH
adenyl cyclase mechanism (cAMP)
mechanism of CRH
adenyl cyclase mechanism (cAMP)
mechanism of calcitonin
adenyl cyclase mechanism (cAMP)
mechanism of PTH
adenyl cyclase mechanism (cAMP)
mechanism of glucagon
adenyl cyclase mechanism (cAMP)
mechanism of beta1 and beta2 receptors (adrenergic)
adenyl cyclase mechanism (cAMP)
mechanism of GHRH
both adenyl cyclase mechanism (cAMP) and phospholipase C mechanism (IP3, Ca)
(depends on tissue and receptor)
mechanism of GnRH
phospholipase C mechanism (IP3/Ca2)
mechanism of TRH
phospholipase C mechanism (IP3/Ca2)
mechanism of angiotensin II
phospholipase C mechanism (IP3/Ca2)
mechanism of ADH v1 receptor (BV)
phospholipase C mechanism (IP3/Ca2)
mechanism of oxytocin
phospholipase C mechanism (IP3/Ca2)
mechanism of alpha 1 receptors
phospholipase C mechanism (IP3/Ca2)
mechanism of glucocorticoids (cortisol)
steroid hormone mechanism
mechanism of estrogen
steroid hormone mechanism
mechanism of progesterone
steroid hormone mechanism
mechanism of testosterone
steroid hormone mechanism
mechanism of aldosterone
steroid hormone mechanism
mechanism of 1,25 dihydroxycholecalciferol
steroid hormone mechanism
mechanism of thyroid hormones
steroid hormone mechanism
mechanism of insulin
tyrosine kinase mechanism
mechanism of IGF-1
tyrosine kinase mechanism
mechanism of ANP
guanylate cyclase mechanism (cGMP)
mechanism of endothelial derived relaxing factor (EDRF)
guanylate cyclase mechanism (cGMP)
mechanism of NO
guanylate cyclase mechanism (cGMP)
what is up-regulation
hormone increases the total number of receptors or increases sensitivity of receptor OR not undergo degradation and rebind to other receptors
what is downregulation
hormone decreases total number of receptors it can bind to or decreases sensitivity of receptor
mechanisms of degradation
- proteolysis
- oxidation/reduction
- hydroxylation
- decarboxylation
- methylation
how are peptides degraded
proteolysis or decarboxylation or hydroxylation
what is proteolysis
breakdown of proteins/peptides
what is redox
loss or gain of electrons that change chemistry, bioactivity, receptor recognition
what is hydroxylation
addition of OH group to decrease steroids or proteins
what is decarboxylation
removal of COOH to decrease peptides or proteins
what is methylation
addition of CH3 to downregulate DNA gene expression
how are hormones eliminated
conjugated with glucuronic acid that passes through glomerular filtration membrane (urine) or sulfate (bile)