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118 terms

Endocrinology

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endocrinology
the study of endocrine glands, the hormones they produce and the effects of these hormones
endocrine gland
a ductless gland that releases a hormone directly into the blood
exocrine gland
a duct gland that releases a hormone or hormones
Ernest Starling
1905 coined the term hormone from the greek word to arouse or excite
Hormone
chemical messenger produced by endocrine glands or cells where they affect the activity of these cells
discovery of hormones
chinese discovered goiters due to enlarged thyroid gland, suggested seaweed to help iodine levels
Hippocrates
came up with the idea that humans illness could be caused by an imbalance of the 4 humors
Aristotle
recognized that if you remove the testis from male animals they do not develop the same way as normals
Berthold's experiment
effects of castration and testis replacement found that male roosters did not develop secondary sexual traits
Brown-Sequard
self-administered aqueous extract of dog and guinea pig testies
bayliss and starling
discovered the first hormone, secretin, done with dogs, cutting the nervous system to the stomach to prevent any interaction then placed acid in the stomach and saw hormone projection from the pancreas
Von Mering and Minkowiski
removed pancreas from dogs and noted excess sugar in urine and blood, blood glucose levels rose past absorption rates in kidneys and lead to a high level of sugar in blood
Banting and Best
isolated extract of insulin from dog pancreas and was able to treat diabetes mellitus 1 with pancreantic islet extract
diabeties
run though
mellitus
sweet
earl sutherland
discovery of the second messenger cAMP
Guillemin and Schally
discovered hypothalamic neurohormones that regulate anterior pituitary gland thyrotopin releasing hormone TRH, suggested a link between hormones and light
rosalyn yallow
developed a method of measuring small amounts of hormones radioimmunoassays
bernard
living organizms have an internal state that has to be kept in balance
cannon
coined the term homeostasis
negative vs positive feedback
negative feedback is far more important
calcitonin
helps to regulate calcium if there is to much in the system made by perafolicular cells in pancreaus
parathormone
helps to regulate calcium if there is not enough in a system
neurohormones
chemical messengers produced by neurosecretory neurons that are transported via the blood to garget cells
neurosecreory neurons
specialized neurons that carry action potentials and release neurohormones
neuromodulators
chemical messengers that stimulate or inhibit responses of neurons to neurotransmitters
peptide=growth stimulating factors
peptides that stimulate cell division
neurotransmitters
chemical messengers produced by nerve cells, which are released from the pre-synaptic membrane, diffuse across a synaptic cleft, and bind to receptors of the postsynaptic membrane of a nerve or muscle cell
common neurotransmitters
acetylcholine, dopamine, serotonin
semiochemicals
chemical messengers that carry information to other animals
pheromones
affects conspecifics, intra-specific effects
allelomones
affect other species, inter-specific effects
releaser pheromones
rapid effects
primer pheromones
long term developmental effects
allomone
emiter benefits
kariomone
recipient benefits
chemical messengers
any substance produced by a cell of endogenous or exogeneous origin that affects the physiological activity of another cell
polypeptide hormones
hormones consisting of amino acids that are joined by peptide bonds, may be stored prior to release, released phasicly, transported free in blood
insulin
a two chained polypeptide hormone
thyrotropin releasing hormone
single chain polypeptide hormone with 3 amino acids
human growth hormone
single chain polypeptide hormone with 191 amino acids
oxytocin
single chain with a ring
androgen
steroids with masculinizing effects
estrogens
steroids with feminizing effects
glucocorticoids
steroid that effect carbohydrate metabolism
steroid and thyroid hormones
transported in blood bound to plasma proteins
equilibrium between bounded hormones, free hormones and plasma proteins
k=[HP]/[H][P]
half-life of hormones in blood
time required for half of molecules to be inactivated or cleared from circulation (t1/2)
catecholamine hormones
deactivated by monoamine oxidase (MOA) and/or catecholamine-o-methyl transferase (COMT)
steroid hormones
sulfation and glucornoide formation makes these soluable in water to get out of system
permissive effect
one hormone must be present for another hormone to act (thyroxine required for GH induced brain growth)
synergistic effect
effect of two or more hormones acting together greater than sum of their individual effects
human endocrine glands
most endocrine glands secrete more than one hormone, placenta is a transient endocrine gland in females, thymus gland atrophies prior to puberty in both sexes
hormone receptors
high specificity, hight affinty (low Kd), hormone binding to receptor initiates biological activity
homospecific up regulation
prolactin increases prolactin receptors
homospecific down regulation
insulin decreases insulin receptors
heterospecific up regulation
estradiol increases progesterone receptors
heterospecific down regulation
thyroxine decreases thyrotropin-releasing hormone receptors
G-protein- coupled receptors GPCRs
largest class, bind polypeptide hormones, neurotransmitters, rhodopsins, odorant molecules, single chain of 7 hydrophobic transmembrane domains separated by hydrophilic segments, receptor when bound to hormone couples to G proteins
G proteins
bind guanine nucleotides, guanosine diphosphate (GDP), guanosine triphosphate (GTP), heterotrimers, alpha subunit type determines whether stimulator or inhibitory effects
activation G protein signal transduction pathway
alpha-GTP activates enzymes, opens ion channels, activation of enzymes and opening of ion channels generates second messengers, pertussis toxin inhibits on reaction only for Gi
deactivation of G protein signal transduction pathway
alpha-GTP termed a GTP-switch protein because of its intrinsic GRPase activity, cholera toxin inhibits off reaction
membrane receptors with intrinsic enzymatic activity
receptors with tyrosine kinase activity (RTK), receptors with guanlate cyclase activty, not 7-transmembrane receptors, do not associate with G proteins
receptor tyrosine kinases (RTKs)
tyrosine kinase part of receptor, hormone binding to receptor activates tyrosine kinase, receptor for insulin and epidermal growth factor
receptor with guanylate cyclase activty
guanylate cyclase part of receptor, receptor for atrial natriuretic factor (ANF)
receptor with guanylate cyclase activity
guanylate cyclase part of receptor, receptor for atrial natriuretic factor ANF
tyrosine kinase-associate receptor
tyrosine kinase not part of receptor instead non covalent associated, hormone binding causes formation of dimeric receptor that activates tyrosine kinase in cytoplasm, receptor for GH, prolactin, erythropoietin, cytokines such as interferons
cyclin adenosine monophosphate cAMP second messenger
hormone-receptor binding increases adenylate cyclase activity, adenylate cyclase converts ATP to cAMP second messenger, cAMP activates cAMP-dependent protein kinase PKA, PKA phosphorylates proteins
deactivation of cAMP second messenger
cyclin AMP phosphodiesterase converts cAMP to inactive AMP, phosphodiesterase inhibited by methyl xanthines
cyclic guanosine monophosphate cGMP 2nd messenger
transmembrane form as well as soluble form of gyanylate cyclase, cGMP inactivated by cGMP phosphodiesterase
calmodulin
cellular calcium receptor in all eukaryotic cells, four ca2+ binding sites, structurally similar to troponin c, biologically activated when calcium binds to at least three of the four calcium binding sites, activates Ca2+ calmoduline-dependent kinase, stimulates ATPase that pumps Ca2+ out of cells or into storage depots (mitochondria and smooth ER), activates myosin light chain kinase in smooth muscle
Cyclooxygenase1 inhibitors
basal, nonsteroidal anti-inflammatory drugs (NSAIDS), aspirin, ibuprofin, indomethacin
COX2 inhibitors
induced, selective inhibitors (COXIBS), celebrex, vioxx
COX3
brain, tylenol
5-lipoxygenase inhibitors
singulair, treatment of asthma and allergies
prostaglandins
affect smooth muscle activity, increased PGF2alpha: contractions, increased PGE2: relaxation
prostacyclins
inhibit blood platelet aggregation, syntesized by endothelial cells of blood vessels, travel to platelets and decrease free Ca2+
thromboxanes
stimulate blood platelet aggregation, synthesized by blood platelets, clotting stimuli such as thrombin stimulate synthesis, increase free Ca2+ and change platelet shape
leukotrines
increase smooth-muscle contraction, blood vessel permeability, and mucosus secretion in airways, synthesized and released by leukocytes, components of inflamatory response
labor
increased PGF2 alpha, associated with onset, PG inhibitors help prevent premature labor, increased PGF2 alpha decreased bleeding from umbilical cord
abortion
intrauterin devises increase PGF2 alpha
dysmenorrhea
painful menstrual crams, excess PGF2 alpha synthesis, treat with PG synthesis inhibitors
ductus arteriosus
closes at birth in part because of decreased PG exposure, PG inhibitors used to close duct in premature infants
blood clots
to much thromboxane and or to little prostacyclin increases tendency of blood to clot, asprinin is an effective treatment because thromboxane synthesis inhibited more than prostacyclin synthesis
inflammation of arteries
excess leukotrines synthesis causes inflammatory response in arterial wall, treat with leukotrine synthesis inhibitors
stomach ulcers
PG required for normal mucus production, PG treatment to health stomach ulcers
asthma and allergies
leukotrines case contraction of small airway passages in lungs, singulair to treat asthma and allergies
intracellular receptors class 1
receptors of steroid hormones, located in cytoplasm or nucleus, associated with heat shock proteins HSPs when not bound to ligand, when bound to hormone form homodimers that bind to hormone response elements HRSs
extripation and replacement
classic method removal and replacement
ectopic site
site other than normal site
monoclonal antibodies
antibodies produced from hybridomas
hybridomas
formed by cellular fusion of a beta lymphocyte and a myeloma, large amounts of specific antibodies obtained from hybridomas
chemical ablation
use of chemicals or drugs to destroy endocrine function, alloxan or streptozotocin to destroy beta cells o islets of langerhands
hematoxylin
basic dye, interacts with acidic cellular components
eosin
acidic dye, interacts with basic cellular components
bioassays
study of hormonal action in living systems
pigeon crop assays for prolactin
epithelial cell height positively correlated with PRL levels, determine PRL levels using dose-response curve
friedman test
rabbit test for human chronic gonadotropin (hCG), urine from women suspected for being pregnant injected into female rabbit, if woman is pregnant, hCG stimulates rabbit ovaries to form corpora lutca, antibody test for hCG now used
toad bladder/frog skin response to arginine vasopressin (AVP)
use to study mechanism of action of AVP on movement of water across membranes
agonists
mimic action of hormones, diethylstilbestrol (DES), an estradiol (E) agonist
antagonists
inhibit action of hormones, tamoxifen, and E antagonist in breat tissue
autoradiography
method that uses radioactive labeling to determine anatomical location of hormones
immunocytochemistry
antibody-based procedure for visualizing location of substance, antibody to substance of interest conjugated to a fluorescent dye or enzyme
C-fos gene
expression in hippocampus an immediate early gene
c-fos protein
a transcription factor expression in hippocampus
insulin
lowers concentration of glucose in blood
glucagon
raises the concentration of glucose in the blood
radioimmunoassay
curves are inverse, the higher the viral count the lower the testosterone levels
enzyme immunoassay
quantitative measurement of hormones, hormone labeled with enzyme rather than radioactive isotope
spectrophotomer
used to measure bound labeled hormone as indicated by color change caused by enzyme reacting with added substrate
hybridization
annealing or paring of complementary strands of nucleic acid
blot test
determine whether particular nucleic acid or protein present, tissue homogenized and cells lysed with detergent homogenate placed on introcellulose filter, filter incubated with labeled complementary nucleic acid or protein antibody
in situ hybridization
percise cellular location of RNA or DNA of interest, hybridization of labeled probe occurs within cell
antisense oligonucleotides
a method to inactivate specific mRNAs
morpholino oligos
a synthetic form of antisense oligonucleotides
RNA interference (post transcriptional gene silencing)
injection of double stranded RNA to silence specific genes by interfering with their mRNA, dsRNA digested by enzyme to small interfering RNAs (siRNAs)
vertebrate transgenic animals
gene introduction from one species to another, rat GH gene transferred to mice
knockout gene method
disruption of natural occurring gene