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106 Cards in this Set

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arachidonic acid derivatives that are derived from phospholipids
eicosanoids
cholesterol derivatives
steroids
function of pituitary gland
receives input from hypothalamus and releases appropriate homrones into systemic circulation
2 major mechanisms for hormone inactivation
1- inactivation by enzymes
2- inactivation via removal from receptor area
3 main mechanisms for regulation of hormone synthesis
negative control, positive control, feedback inhibition
tumor formation commonly results in ______ of a particular hormone
overproduction
Autoimmune disorders or genetic defects often cause ______ of a particular hormone
underproduction
Caused by a lack of functional receptors due to genetic defects, autoimmune disorders or overstimulation and downregulation of receptors
target cell insensitivity
AVP/ADH--function?
stimulates water reabsorption in principal cells of collecting ducts and constriction of arterioles
AVP/ADH--origin?
posterior pituitary
Oxytocin--function?
stimulates milk ejection from breasts and causes uterine contractions (child birth and copulation)
Oxytocin--origin?
posterior pituitary
Thyroid stimulating hormone (TSH): origin and function
anterior pituitary; stimulates synthesis and secretion of thyroid hormones
Follicle-stimulating hormone (FSH)
anterior pituitary; stimulates sperm maturation in Sertoli cells and follicular development and estrogen syntesis in ovaries.
Luteinizing hormone (LH)
anterior pituitary; stimulates testosterone synthesis in Leydig cells, stimulates ovulation, formation of corpus luteum, estrogen and progesterone synthesis in ovaries
Growth hormone: origin and function
anterior pituitary; stimulates protein synthesis and overall growth
Prolactin: origin and function
anterior pituitary; stimulates milk production and secretion in breast
Adrenocorticotropic-hormone (ACTH): origin and function
anterior pituitary; stimulates synthesis and secretion of adrenal cortical hormones (cortisol, androgens, aldosterone)
Melanocyte-stimulating hormone (MSH): origin and function
anterior pituitary; stimulates melanin synthesis
Thyrotropin-releasing hormong (TRH): origin and function
hypothalamus; simulates secretion of TSH and prolactin
Corticotropin-releasing hormone (CRH): origin and function
hypothalamus; stimulates secretion of ACTH
Gonadotropin-releasing hormone (GnRH): origin and function
hypothalamus; stimulates secretion of FSH and LH
Somatostatin or Somatotropin release-inhibiting homrone (SRIF): origin and function
hypothalamus; inhibits secretion of growth hormone
Dopamine or Prolactin-ihibiting factor (PIF): origin and function
hypothalamus; inhibits secretion of prolactin
Growth hormone-releasing hormone (GHRH)
hypothalamus; stimultes secretion of GH
Calcitonin
thyroid; decreases serum calcium
increases serum calcium conc
parathyroid hormone
stimulates estrogen and progesterone synthesis in corpus luteum of early pregnancy
hCG (human chorinic gonadotropin)
has GH-like and prolactin-like actions during pregnancy
human placental lactogen (hPL) or human chorionic somatomammotropin
catalyzes conversion of angiotensinogen to angiotensis I
renin; released by kidney
contains a 15-25 residue signal sequence of mostly hydrophobic amino acids at its N-terminus that allows entry into the ER
pre-prohormone
are peptide hormones stored in secretory granules?
yes: they are packaged by the TGN into immature secretory granules along with their processing enzymes and other required proteins
An acidic environment in the immature secretory granules is required for what process?
cleavage on carboxy side of paired basic residues of the prohormone (i.e., lysine or arginine)
What process follows cleavage at paired basic residues?
peptide hormones are amidated, which makes them more biologically active and helps preserve their half-life once secreted
enzyme that amidates prohormones
PAM (peptidylGlydie-a-amidating monooxygenase )
prohormone from which ACTH and beta-LPH are made
pro-opiomelanocortin (POMC)
what is responsible for the differential processing of POMC?
enzyme location; conditions (stress, etc.)
inhibits release of CRH at hypothalamus and release of ACTH at anterior pituitary(via feedback inhibition)
cortisol
inhibits release of ACTH from anterior pituitary via negative inhibition
dopamine
In episodic/circadian secretion, which is secreted first: cortisol or ACTH?
ACTH--ACTH causes release of cortisol which then directly inhibits ATCH production and release from the pituitary
Cushing's Disease or Syndrome: caused by ACTH secreting tumors of pituitary
Disease
Adenoma of adrenal cortex causes release of excess cortisol due to overproduction...what disease?
Cushing's Syndrome
ketoconazole and metyrapone are used to treat what disease?
Cushing's Syndrome
treatment for Cushing's disease?
surgical removal o ACTH secreting tumor
The following symptoms describe what disease: polyuria, polydipsia, dehydration, weakness, mental retardation if not treated
Diabetes insipidus
What type of Diabetes Insipidus is caused by a loss of functionality of AVP receptor in the kidney (usually mutations)
Nephrogenic---treat with ibuprofen
What type of Diabetes Insipidus develops during pregnancy and dissappears 4-6 weeks after delivery?
Gestational--treat with desmopressin (synthetic AVP) and time
What type of Diabetes Insipidus is caused by suppression of vasopressin by excessive intake of fluids?
Dipsogenic--treat by decreasing water intake
What type of Diabetes Insipidus is characterized by a defect int he secretion of AVP from the posterior pituitary, is inherited (via x-linked or autosomal dominant)?
Neurogenic--treat with desmopressin (synthetic AVP)
Enzyme that iodinates thyroglobin
thyroidal peroxidase (TPO)
synthesized in thyroid follicular cells stored as a part of thryoglobin
MIT and DIT (monoiodotyrosine and diiodotyrosine)
where is TPO located?
apical border of thyroid acinar cell
coupling reactions of MIT and DIT form what 2 hormones
T3 and T4
stored in colloidal space where it is iodinated
thryoglobulin (TGb)
what stimulates endocytosis of TGb at apical membrane of acinar cell?
binding of TSH to receptor on basal membrane
What happens in endosomes following endocytosis of TGb?
proteases from lysosomes cleave peptide bonds to form T3 and T4 that are released into circulation and MIT and DIT which are recycled
how are MIT and DIT recycled?
deiodinase breaks MIT and DIT down into tyrosine and iodine
90% T4 and 10% T3 but T3 is more active---why 90/10?
major pathway of thyroid metabolism is sequential deiodination, thus 80% of circulating T3 is dervied from T4
major site of T3 and T4 degradation
liver (minor sites are kidney and other tissues)
thyroid hormones can be conjugated with sulfaces and glucuronides and excreted into bile so that they can undergo what process?
enterhepatic circulation
thyroid hormones are primarily eliminated via what organ
kidneys--but some conjugated hormone is eliminated in feces
T3 and T4 exhibit feedback inhibition...affects secretion of what?
TRH, TSH
What disease: lowered basal metabolic rate, diastolic hypertension, goiter
hypothyroidism (insufficient T3/T4)
What disease: increased metabolic rate, exophthalmos, goiter
hyperthyroidism (autoimmune---Anitbodies to TSH receptor)
Levothyroxine treats what disease?
hypothyroidism
Treatment options for hyperthyroidism
surgical resection/ 131-Iodide to destroy the hyperfunctioning cell population
When thryroid failure results in decreased T3/T4, what is the response of the pituitary?
increased secretion of TSH--goiter forms because the only way to keep up/increase production of T3/T4 is to enlarge
Antibodies to TSH receptor cause its activation and body thinks it needs more T3/T4 even though it may not. What results from this?
Goiter--gland increases size to keep up production of T3/T4
common characteristics of Serotonin, Melatonin and Catecholamines
derived from amino acids, small molecules, neurotransmitters
major elements in response to severe stress
catecholamines
increases HR and SV, dilates pupils, constricts skin and gut arterioles and dilates arterioles in leg muscles, increases blood sugar, increases lipolysis, suppresses immune system
epinephrine (and norepinephrine)
dopamine
neurotransmitter as well as hormone that inhibits release of prolactin
T or F: catecholamines can cross the blood-brain barrier
Falso, must be synthesized in CNS...L-DOPA can cross though
synthesis location of Epi, NE, and Dopamine
Epi-adrenal medulla
NE-mainly in sympathetic nerves, also adrenal medulla and CNS
Dopamine- CNS
Precursor for all catecholamines
Tyrosine
rate limiting steop for catecholamine synthesis
tyrosine hydroxylase, which is activated by a cAMP-dependent protein kinase
Type of secretion for catecholamines: constituative or regulated
regulated (secretory granules)
2 regulation methods for catecholamines
degradation by MAO and re-uptake
path from tyrosine to epinephrine
Tyrosine→DOPA→Dopamine→NE→Epi
works with MAO to metabolize catetcholamines
catechol-O-methyltransferase (COMT)--methylates hydroxyl group
Disease? : slight male predominance, can be caused by infection, toxins, drugs, association with other neurodegenerative disorders, trauma, metabolic disorders and multiple infarct...present with tremors
Parkinson's Disease
Carbidopa treats what?
peripheral decarboxylase inhibitor that treats Parkinson's
active ingredient of what treatment for Parkinson's is precursor to dopamine?
levodopa
Dopamine agonists used as adjunct to L-Dopa
Bromocriptine, Pergolide
Disease: excess production of catecholamines resultig in hypertension and tachycardia
Pheochromocytomas--tumors of adreanal medulla or sympathetic ganglia
Treatment for Pheochromocytomas
surgical resection of tumos, radiation thereapy, chemotherapy
Plays a role in regulation of mood, sleep, emesis, sexuality and appetite; plays a part in depression, migraines, bipolar disorder, anxiety
Serotonin
other roles: liver regeneration, acts as mitogen throughout body, vasocontrictor in blood serum
Melatonin is regulated by dark/light and thus regualtes sleep/wake cycles. When is it released/suppressed?
Released during darkness, suppressed by daylight
What is melatonin used for clinically?
inducing sleep, preventing jet lag (works best at times wen it is not being produced in high quanitity)
Synthesis location of Serotonin and Melatonin
Pineal gland
-Serotonin also secreted by small intestine
Precursor to serotonin and melatonin? rate limiting step?
Tryptophan; tryptophan hydroxylase
Enzyme responsible for conversion of N-acetylserotonin to melatonin?
hydroxyindol-O-methyl transferase (HIOMT)
Serotonin and Melatonin: constituative or regulated secretion?
regulated
Degradation of Serotonin/Melatonin
both broken down by MAO
5HT removed by transport protein--must be removed for it will continue to elicit response
What Disease: depressed mood caused by chemical imbalance
Depression
Treatment for depression?
inhibit MAO or prevent removal of NTs from synaptic cleft--SSRIs: serotonin specific re-uptake inhibitors (fluoxetine and paroxetine)
generic names for Prozac and Paxil and potentian risks
Prozac: Fluoxetine--potential for low birth weight, premature labor and heart defects for fetus
Paxil: Paroxetine--potential for lung defects
What disease? genetic, defective absortption of tryptophan, symptoms include photosensitive dermatitis, intermittent neurological symptoms, and blue diaper syndrome (indicanuria)
Hartnup's Disease--autosomal recessive
Treatment for Hartnup's syndrome?
high protein diet with di-peptide tryptophan (di-peptides can be absorbed via di-peptide transporter)
H-dependent ACh transporter in synaptic vesicles is responsible for what?
concentration of ACh
enzymes that process ACh
CHAT--synthesis
AChE--degradation
Degradation of ACh
hydrolysis by AChE into choline and acetate--choline is taken up by nerve terminal and ACh is resynthesized by CHAT then concentrated into vesicles
What disease? symptoms of double vision, ptosis, difficulting swallowing, generalized weakness caused by anitbodies against ACh receptors
myasthenia gravis
Treatment for myastenia gravis?
Pyridostigmine--AChE inhibitor
Organophosphates inhibit AChE resulting in what?
hypercholinergic effect due to buildup of ACh in synapses
Treatment for hypercholingeric effects of chemical exposure?
atropine, diazepam, pralidoxime