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5 Cards in this Set
- Front
- Back
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Compare the synthesis of peptide/polypeptide hormones, lipid derivative hormones and amine hormones. Give an example of each.
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Peptide/polypeptide hormone synthesis: mRNA preprohormone --> signal sequence cleaved off in ER to prohormone --> move through golgi --> cleaved to active hormone in golgi --> packed into secretory vesicles and STORED for later release; INSULIN
Lipid Derivative hormone synthesis: cholesterol is in the cell (from HSL action on lipid droplet) and is taken into the mitochondria by STAR protein --> cholesterol converted to pregnenolone by CYP11A --> --> --> used immediately NOT STORED; STEROIDS **note- ACTH upregulates the action of HSL to break down lipid drops to free cholesterol and upregulates STAR protein Amine hormone synthesis: synthesized from precursor and STORED; T3/T4, catecholamines |
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Compare the half lives of peptide/polypeptide hormones, steroids and amine hormones. Why is this?
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peptide/polypeptide- water soluble, not protein bound --> short half life
steroids and amines are not water soluble, so they are bound to proteins --> longer half life |
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Where are the cell signaling mechanisms located for peptide hormones? Steroid hormones?
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Peptide hormones use cell surface receptors.
Steroid hormones use intracellular (nuclear) receptors. |
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List some examples of hormones that use:
GPCR Tyrosine Kinase Nuclear Receptors |
GPCR: FLAT ChAMP (from FA), her specific examples were FSH, LH, TSH, MSH, PTH, glucagon, TRH, catecholamines
Tyrosine Kinase- insulin, GH, prolactin Nuclear Receptors (aka steroid receptors)- vit D, T3/T4 |
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How can desensitization occur with cell signaling? (4)
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1. Uncoupling GPCR from G protein after binding
2. Endocytosis 3. Modification 4. Decrease Expression |
