Term
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Definition
| Regulatory chemical produced in an endocrine gland or scattered cells, secreted into the blood and carried to its target cell that responds by altering its metabolism |
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Definition
| acts at a distance from the release site |
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Definition
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Definition
| acts on its own secreting cell |
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Definition
| synthesized by nervous tissue and carried in the blood |
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Term
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Definition
| released by nervous cells in contact with target cells |
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Term
| Why should pheromones count as hormones? |
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Definition
| They are essentially hormones that regulate members of a population |
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Term
| What is an additive/concerted response to hormones? |
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Definition
| Two hormones act to increase an activity, and the effects of each contribute the same together as they did separately |
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Term
| What is a non-additive response to hormones? |
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Definition
| Together they produce a positive response but not the added response of both of them |
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Term
| What is an antagonistic response to hormones? |
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Definition
| The positive response of one hormone is cancelled out by another one. |
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Term
| What is a synergistic response to hormones? |
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Definition
| The combined response to two hormones is greater than the two of them put together |
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Term
| What is a permissive response to hormones? |
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Definition
| The combination of two hormones produces a high response despite a non-response from one alone. |
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Term
| What is the range of amounts hormones can be released in? |
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Definition
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Term
| Amount of hormone available to target cells depends on what? (3) |
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Definition
| level of synthesis and release, level of biological activity, level of turnover |
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Term
| Properties used to define hormones? |
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Definition
| Produced by specific cells to act on target tissues, hormone levels higher in blood draining gland, determination of origin,reversal of effects, purification of producing cell extract increases potency |
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Term
| What are the two methods by which hormones can control gene expression? |
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Definition
| Regulate gene transcription-->RNA stability, regulate RNA translation-->protein stability |
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Term
| What are the 3 main actions of hormones on cells? |
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Definition
| Control of gene expression, modulate activity, alter cellular transport and membrane permeability |
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Term
| By what methods can hormones alter cellular transport and membrane permeability? |
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Definition
| -intracellular trafficking; transport process, polarity, water permeability; exocrine secretion |
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Term
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Definition
| morphological changes, cell division/differentiation, protein synthesis, enzyme regulation, muscle contraction, control of exocrine/endocrine secretion, permeability of water, effect on behaviour |
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Term
| 4 classes of hormones? (4) |
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Definition
-Polypeptides, proteins and glycoproteins
-Steroid hormones
-Amino-acid derivatives
-Fatty acid derivatives or eicosanoids |
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Term
| How are polypeptide based hormones produced, stored and secreted? |
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Definition
| produced by genes, water-soluble, accumulate in Golgi vesicles, secreted by exocytosis |
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Term
| How are steroid hormones produced? |
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Definition
| Stepwise conversion of cholesterol by multitude of enzymes, lipid-soluble, produced and secreted as needed |
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Term
| From which amino acids are amino-acid derivative hormones generally produced? |
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Definition
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Term
| Production of fatty acid derivative hormones? |
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Definition
| Derived from cell membrane phospholipids (arachidonic acid), produced locally, mainly autocrine and paracrine effects |
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Term
| Two methods of post-translational modification? |
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Definition
| Glycosylation:carb chains attached for long term change. Phosphorylation: phosphate attached for short term change |
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Term
| Signal for importing into the nucleus? |
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Definition
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Term
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Definition
| Protein synthesized as large precursor molecule |
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Term
| Common and different structure of pituitary hormones? |
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Definition
| LH, FSH, TSH: Common alpha subunit, unique beta subunit |
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Term
| How are protein hormones released and why? |
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Definition
| Exocytosis, they are water-soluble |
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Term
| Main synthesis sites of steroid hormones? |
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Definition
| Testis, ovary, adrenal cortex |
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Term
| Main enzymes involved in synthesis of steroid hormones? |
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Definition
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Term
| Notable characteristics of cytochrome P450? |
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Definition
| -electron transport chain, uses oxygen, has a heme prosthetic group, can serve as a detox agent |
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Term
| 5 major classes of steroid hormones? |
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Definition
| Progestins, estrogens, androgens, glucocorticoids, mineralocorticoids |
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Term
| Steps to convert cholesterol to pregnenolone? |
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Definition
| Hydroxylation of C20 and C22, Cleavage between C20 and C22 (stim by ACTH occurs in mitochondria) |
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Term
| Convert pregnenolone to progesterone? |
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Definition
| Oxidize 3 OH to 3 keto group, isomerize delta 5 to delta 4 |
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Term
| Convert progesterone to cortisol |
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Definition
| Hydroxylation at C17, C21, C11 |
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Term
| Convert progesterone to aldosterone |
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Definition
| Hydroxylation at C11, C21; oxidize C18 to aldehyde |
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Term
| Convert progesterone to androgens |
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Definition
| Hydroxylation at C17, cleavage of side chain, reduce C17 keto to OH |
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Term
| Convert androgens to estrogens? |
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Definition
| Loss of C19 methyl group, aromatization of A ring |
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Term
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Definition
| stimulate inflammation, regulate blood flow, blood clot formation, affect ion transport, modulate synaptic transmission |
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Term
| Where are eicosanoids produced and from what? |
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Definition
| Cell membrane from arachidonic acid derived from phospholipids |
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Term
| How do NSAIDs affect eicosanoid production? |
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Definition
| Inhibit synthesis via cyclooxygenase |
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Term
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Definition
| prostaglandins, prostacyclin, thromboxanes, leukotrienes |
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Term
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Definition
| Act mainly on vascular smooth muscle |
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Term
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Definition
| Produced in blood vessels, inhibit platelet aggregation |
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Term
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Definition
| Produced by platelets, help blood clot formation |
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Term
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Definition
| Produced by leukocytes, potent vasoconstrictor and permeability inducers |
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Term
| How is iodine transported into the thyroid? |
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Definition
| Iodide actively transported through follicular cells (I/Na symport) |
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Term
| Structure of thyroglobulin? |
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Definition
| glycoprotein with over 120 tyrosine residues, released in lumen |
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Term
| How does Tgb get iodinized? |
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Definition
| Tyrosine peroxidase (TPO) binds I2 to tyrosine residues on Tgb |
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Term
| What percentage of thyroid hormones do T3 and T4 account for? |
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Definition
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Term
| How do thyroid hormones exit the thyroid? |
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Definition
| Lipophilic-diffuse across basal membrane, interstitial space, blood capillaries |
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Term
| How are monoamines synthesized? |
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Definition
| Modification of tyrosine to dopamine, norepinephrine and epinephrine (tyrosine from diet or conversion of phenylalanine in liver) |
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Term
| What secretes catecholamines and what is the ratio of the 2? |
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Definition
| Adrenal medulla, epinephrine and norepinephrine are 4:1. |
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Term
| Serotonin: derived from? found in? |
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Definition
| Tryptophan; CNS, GI and platelets |
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Term
| Histamine: released by? derived from? |
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Definition
| Basophils and mast cells; decarboxylation of L-histidine |
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Term
| Acetylcholine: results from? |
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Definition
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Term
| 3 major control pathways? |
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Definition
| trophic hormones, nervous stimuli, metabolite levels |
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Term
| Examples of lipophilic and water-soluble hormones? |
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Definition
| Steroid and thyroid; proteins and catecholamines |
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Term
| Examples of specific and non-specific carriers? |
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Definition
| globulins; albumin and prealbumin |
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Term
| Which water-soluble hormone binds to a carrier? |
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Definition
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Term
| Where and how are peptide hormones degraded? |
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Definition
| By peptidases such as cathepsin mainly in lysosomes of target cells |
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Term
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Definition
| Degrade at specific internal sites |
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Term
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Definition
| Degrade from end, one amino acid at a time |
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Term
| Describe the 2 phase process of degradation of steroid hormones in the kidney and liver. |
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Definition
| Phase 1: Inactivation->intro of extra functional groups by cytochrome P450. Phase 2: Increase water soluble-> conjugation to sulfate or glucuronic acid. More water soluble and excreted in urine or in bile salts |
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Term
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Definition
| Storage form of steroid hormones |
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Term
| Experimental evidence of cell surface receptors? (5) |
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Definition
| Antibody against receptor blocks signalling, limited proteolysis of intact cells blocks response, coupling of hormones with large molecule to inhibit entry into cell maintains hormone effect, membrane fragments retain hormone binding capacity, solubilization of membrane with detergent permits receptor purification |
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Term
| Receptor type= G-protein 2nd messenger=? |
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Definition
| Adenylate cyclase; cAMP, Phosphlipase C; Ca2+ |
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Term
| Receptor type= tyrosine kinase 2nd messenger=? |
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Definition
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Term
| Receptor type= interleukin family (cytokine receptors) 2nd messenger=? |
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Definition
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Term
| Receptor type= TGFBeta family (serine kinase receptors) 2nd messenger=? |
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Definition
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Term
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Definition
| 7 transmembrane helices that change conformation with ligand binding |
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Term
| Experimental evidence for involvement of cAMP? |
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Definition
| Test hormone action by measuring changes in intracellular cAMP, mimic response with exogenous cAMP or its analogues, activate adenylyl cyclase with forskolin to mimic hormone effect |
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Term
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Definition
| Dibutyryl cAMP, 8-bromo cAMP |
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Term
| Phosphodiesterase inhibitors? |
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Definition
| Theophylline, caffeine, 1-methyl-3-isobutylxanthine |
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Term
| Experimental methods of studying PLC/Ca/PKC pathway? |
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Definition
| Inhibit PLC with U73122 to block action of hormone, increase intracellular Ca2+ using Ca2+ selective ionophores or liposomes loaded with Ca2+, blocking movement of Ca 2+ using:-chelating agent like EGTA-Ca channel blockers-Inorganic Ca antagonist, Artificially activate PKC with phorbol esters should mimic the effect of hormone |
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Term
| What is Imatinib and how does it work? |
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Definition
| Used in cancer treatment. Competitively inhibits BCR-ABL tyrosine kinase which is required for growth of tumour cells in chronic myelogenous leukemia |
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Term
| Mechanism of tyrosine kinase receptor action? |
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Definition
| Hormone binding causes activation and dimerization of receptors. Kinase domains in monomers are autophosphorylated. |
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Term
| 3 classes of tyrosine kinase receptor? |
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Definition
| Class 1: epidermal growth factor, Class 2:Insulin and IGF type, Class 3:Platelet-derived growth factor or nerve growth factor |
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