Term
| Different kinds of signaling (communication) |
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Definition
autocrine- same cell secretes and receives hormones. effects: local and short lived.
paracrine- secreting cell and it neighbor receive hormone. effects: nearby and long-lived
endocrine- gland secretes hormone; hormone travels through bloodstream; distant target tissues/cells react. effects: systemic and long-lived |
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Term
| Control of hormone synthesis |
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Definition
CNS control- hypothalamus-pituitary axis
Cellular sensors- [glucose], [Ca2+], [K+] |
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Term
| Chemical nature of hormones- three chemical families |
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Definition
1. polypeptide based hormones: insulin, parathyroid, oxytocin. genetically encoded, amino-acid based. sometimes prohormone precursors
2. steroid hormones: cortisone, testosterone, estradiol. synthesized from terpenes (cholesterol). unique enzymes
3. amino acid/fatty acid derived hormones: epinephrine, prostaglandin, melatonin. synthesized from fatty acids or metabolized amino acids. unique enzymes |
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Term
| secretion, transport, and uptake of polypeptide hormones and hydrophilic hormones |
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Definition
secretion- usually exocytosis
transport- freely circulating
uptake- cell surface receptors or transporters |
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Term
| secretion, transport, and uptake of steroid/fatty acid/amino acid derived |
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Definition
secretion- usually by diffusion
transport- hydrophobic hormones use transporter proteins
uptake- free hormone can diffuse through cell membranes. protein bound hormone acts as a reserve pool. some hormones have specific transporters |
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Term
| mode of action of epinephrine (stress hormone) |
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Definition
-binds to beta-adrenergic receptor (GPCR)
-initiates signal transduction cascade
-induced immediate response
-glycogen breakdown/glucose release |
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Term
| mode of action of cortisol (stress hormone) |
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Definition
-binds to glucocorticoid receptor (nuclear hormone receptor)
-regulates gene transcription, and thus translation/protein production
-induces long term, persistent biological response
-induces gluconeogenic enzymes |
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Term
| Halting production of hormone- negative feedback loops |
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Definition
1. endocrine organ senses change in concentration of a marker, shuts down production of hormone- glucose levels dictate production of insulin
2. CNS senses change in concentration of a marker, sends message to endocrine organ to stop production- thyroid hormone dictates thyroid releasing hormone production in hypothalamus |
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Term
| Halting response of receptor- desensitization (modulation of receptor activity/numbers) |
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Definition
1. phosphorylation of receptors (Fast)- decreased affinity for hormones, decreased signaling
2. internalization and degradation of receptors (slower)- phosphorylation leads to removal of receptors
3. decreased synthesis of receptors (slowest) |
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Term
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Definition
-long term agonist treatment might cause endocrine organ atrophy and loss of function
-antagonist therapy might cause increase in hormone production |
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Term
| Dosing- desensitization issue |
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Definition
-natural hormone production- pulsatile
-therapeutic hormone delivery- worry about desensitization |
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Term
| classic model of hormone action |
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Definition
1. steroid hormone passes through plasma membrane. binds to target receptor in cytosol
2. accessory proteins released, hormone receptor (active form) goes to nucleus
3. HR dimerization, associates with DNA
4. transcription of genes
5. mRNA
6. translation
7. protein |
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Term
| steroid hormone receptor structure |
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Definition
-DNA binding domain (DBD)
-Ligand binding domain (LBD) |
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Term
| other nuclear hormone receptors |
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Definition
-PPAR receptors
-retinoid receptors
-thyroid hormone receptors
-LXR, FXR, CAR, PXR
-orphan nuclear hormone receptors |
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