Term
| What is the mechanism of action for neurotransmitters? |
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Definition
| released from axons to transmit from neuron to neuron |
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Term
| What is the mechanism of action for endocrine hormones? |
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Definition
| released from a gland to affect distant tissue(s) |
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Term
| What is the mechanism of action for neuroendocrine hormones? |
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Definition
| released from an axon into blood to affect distant tissue(s) |
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Term
| What is the mechanism of action for paracrine hormones? |
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Definition
| released from cells to affect nearby tissue(s) |
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Term
| What is the mechanism of action for autocrine hormones? |
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Definition
| released from cells to affect the same tissues that secreted them |
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Term
| What is the mechanism of action for cytokines? |
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Definition
| released from cells; may act as enocrine, autocrine, or paracrine |
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Term
| List the general classes of hormones and give one example of each |
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Definition
Gases - nitric oxide
Steroids - cortisol (glucocorticoids), aldosterone (mineralocorticoids), sex hormones
Amino acid derivatives - thyroxine, epinephrine, norepinephrine, T3, histamine, serotonin
Peptides - insulin, pituitary hormones, hypothalamus hormones, glucagon, parathyroid hormone
Eicosanoids - celebrex, vioxx |
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Term
| What is the method of synthesis for most peptides? |
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Definition
| synthesis from amino acids in rough ER as preprohormones, converted to prohormones, converted to hormones |
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Term
| What is the method of storage for most peptides? |
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Definition
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Term
| What is the method of secretion for most peptides? |
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Definition
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Term
| How long does peptide hormone activity usually last? |
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Definition
| usually only a few minutes |
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Term
| What is the method of synthesis for steroids? |
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Definition
| synthesized from cholesterol from LDL (in the mitochondria) |
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Term
| What is the method of storage for steroids? |
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Definition
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Term
| What is the method of secretion for steroids? |
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Definition
| they pass through the membrane |
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Term
| What is the method of transport for steroids? |
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Definition
| usually via carrier proteins, though sometimes dissolved in blood |
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Term
| What is the method of transport for peptides? |
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Definition
| usually dissolved in blood |
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Term
| What is the location of receptors for peptides? |
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Definition
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Term
| What is the location of receptors for steroids? |
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Definition
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Term
| What is the duration for steroids? |
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Definition
| usually long - may vary from 20 minutes (aldosterone) to days |
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Term
| What is the method of synthesis for eicosanoids? |
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Definition
| made from arachadonic acid |
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Term
| What is the method of storage for eicosanoids? |
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Definition
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Term
| What is the location of receptor for eicosanoids? |
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Definition
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Term
| What is the duration for eicosanoids? |
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Definition
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Term
| What is the method of synthesis for gas hormones? |
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Definition
| (for nitric oxide) made from arginine and oxygen by Ca2+-dependent synthase |
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Term
| What is the method of storage for gas hormones? |
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Definition
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Term
| What is the method of secretion for gas hormones? |
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Definition
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Term
| What is the method of transport for gas hormones? |
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Definition
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Term
| What is the duration for gas hormones? |
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Definition
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Term
| What is the location for receptors for gas hormones? |
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Definition
| varies based on tissue: sometimes none |
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Term
| How do you determine the rate of disappearance of a hormone from plasma? |
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Definition
| infusion of radioactive hormone until infusion rate is steady; at this point, infusion rate = rate of disappearance |
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Term
| What are the three possible locations of cells receptors? |
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Definition
| Cell surface, intracellular, nuclear |
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Term
| What is the formula for receptor-hormone affinity? |
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Definition
Kd = ([R][H])/[RH]
Kd - dissociation constant
R - receptor
H - hormone
RH - receptor-hormone complex |
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Term
| Describe the mechanism of intracellular receptors |
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Definition
| Mention: 1. hormone chaperones, 2. binding to promoter (called hormone response element), 3. transcription |
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Term
| Which 2 ligand receptors don't require their ligands to bind to DNA? |
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Definition
| vitamin D and thyroid hormones |
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Term
| Describe thyroid hormone receptor activity |
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Definition
| Mention: 1. receptor bound to DNA, 2. HDAC, 3. when hormone binds HAT switches with HDAC, 4. transcription |
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Term
| Describe G-protein-linked receptor activity |
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Definition
| Mention: 7 transmembrane segments, 2. heterotrimeric GTP-binding proteins, 3. ligand binding, 4. GDP swapped for GTP, 5. subunts part, 6. alpha-GTP activates enzyme |
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Term
| Describe adenylyl cyclase activity |
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Definition
| Mention: 1. produces cAMP from ATP, 2. guanylyl cyclase has some mechanism, 3. often activated by G-protein-linked receptor |
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Term
| State the metabolic clearance rate formula |
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Definition
| MCR = (rate of disappearance of hormone from plasma)/[hormone] |
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Term
| How are hormones "cleared"? |
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Definition
| Hormones are cleared by: 1. metabolic destruction, 2. binding, 3. excretion into the bile by the liver, 4. excretion into the urine by the kidneys |
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Term
| Describe phospholipase C activity |
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Definition
| Mention: 1. may be a target of G-protein-linked receptor, 2. catalyzes breakdown of PIP2, 3. produces IP3 and DAG |
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Term
| What do the products of phospholipase C do? |
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Definition
IP3 - mobilizes calcium from mitochondria and ER
DAG - activates PKC; lipid portion of DAG is arachadonic acid |
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Term
| Describe the activity of calcium as a second messenger/signal transducer |
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Definition
| Mention: 1. entry may be from voltage or ligand-gated channels, 2. calcium binds to calmodulin, 3. when 3-4 of the 4 binding sites are filled, calmodulin changes configuration, 4. multiple effects, including activation or inhibition of protein kinases via phosphorylation |
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Term
| What are the two ways to detect [hormone]? |
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Definition
| radioimmunoassay and enzyme-linked immunosorbent assays (ELISA) |
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Term
| Why is it so hard to detect [hormone]? |
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Definition
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Term
| Which method of [hormone] detection is preferred and why? |
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Definition
| 3. ELISA, because it does not involves radioactive isotopes, it has been proven cost effective, and much of it is automated with 96-well plates |
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Term
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Definition
| Mention: 1. 96-well plates, 2. AB coating, 3. add hormone, 4. add AB2, 5. add AB3 (an enzyme-attached AB), 6. add substrate, 7. use colorimetric and fluorescent detection methods to detect [subtrate]; [substrate] are proportional to [hormone] |
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Term
| Describe radioimmunoassay |
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Definition
| Mention: 1. AB for hormone, 2. add subject's fluid, 3. add radioactive isotoped synthetic hormone, 4. competition for binding site, 5. quantity bound is proportional to [hormone] or [isotoped hormone], 6. isolate AB and analyze radioactive isotope, 7. [isotope] is proportional to 1/[subject's hormone], 8. for quantitative assay, perform with varying [isotope]'s and get a curve to compare to result with patient's [hormone] |
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Term
| Describe receptor tyrosine kinase |
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Definition
| Mention: 1. dimerization, 2. auto-phosphorylation, 3. signal transduction, 4. phosphorylation increased by kinase activity, 5. "cross-talk" |
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Term
| Describe estrogen activity |
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Definition
| Mention: 1. bind to IC receptor, 2. chaperone Hsp90, 3. dimerization, 4. bind to promoter, 5. HAT or HDAC |
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Term
| Describe the mechanism for leptin receptor. |
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Definition
| Mention: 1. passes through membrane once, 2. dimerization, 3. phosphorylation of JAK2, 4. phosphorylation of tyrosine residues, 5. STAT proteins, 6. transcription of leptin target genes |
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Term
| What kind of receptor is the leptin receptor? |
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Definition
| enzyme-linked cytokine receptor |
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Term
| What phosphoylated tyrosine STAT molecules are activated during leptin receptor activation? |
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Definition
1. SH2 (src homology 2) - related to src from Rous sarcoma virus
2. PTB domain proteins - phosphorylated tyrosine binding domain proteins |
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Term
| Describe the mechanism of ion-channel-linked receptor |
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Definition
| Mention: 1. opens and closes quickly, 2. not saturable, 2. may be voltage or ligand-gated, 4. mostly activated through second messenger if ligand-gated |
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Term
| Describe ACh mechanism of ion-channel-linked receptor |
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Definition
| Mention: 1. hydrophobic groups, 2. conformational change |
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Term
| What is the method of synthesis for amine-derived hormones? |
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Definition
| formed from an amino acid in cytoplasmic compartments |
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Term
| What is the method of storage for amine-derived hormones? |
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Definition
| stored in follicles (thyroid) |
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Term
| What is the method of secretion for amine-derived hormones? |
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Definition
| released from follicles into blood stream |
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Term
| What is the method of transport for amine-derived hormones? |
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Definition
| often bound to plasma proteins |
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Term
| What is the location of the receptor for amine-derived hormones? |
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Definition
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Term
| What is the duration for amine-derived hormones? |
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Definition
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Term
| List the benefits to tyrosine-receptor dimerization |
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Definition
| 1. localizes complexes, 2. promotes phosphorylation, 3. stimulates enzyme activity |
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Term
| Give examples of the use of tyrosine-receptor dimerization |
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Definition
| leptin, epidermal growth factor, platelet-derived growth factor, nerve GF, VEGF, macrophage colony-stimulating factor, and insulin (which has a dimer without the need of a ligand) |
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Term
| What are the methods of down-regulation for a hormone? |
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Definition
| 1. inactivation of receptors, 2. inactivation of signaling molecules, 3. sequestration of receptor from site of hormone action to inside the cell (temporary), 4. destruction of internalized receptor, 5. decreased production of receptor |
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Term
| Describe cytokine receptor activity |
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Definition
| Mention: 1. no intrinsic enzyme activity, 2. dimerization, 3. kinase recruitment (NRTKs of JAK or Src family), 4. Phosphorylation, 5. SH2 recruitment, 6. signal transduction |
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Term
| Give examples of cytokine receptors |
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Definition
| erythropoetin, IL-2, IL-6, leptin, hGH |
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