03 Classification of Hormones

03 Classification of Hormones - PSL302: Lecture 03, by...

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Classifcation oF Hormones Peptide (protein): > 3 amino acids Steroid: cholesterol Amine hormones: single amino acid -> Names based on hormone composition to facilitate understanding of how they fxn Peptide Hormone Most common of hormones Made in advance -> synthesized like proteins & stored in vesicles Exocytosis: released into bloodstream upon signal received by secretory cell Water soluble: dissolved & carried in plasma Short half-life: not bound to a carrier in blood = naked and exposed to evmt Bind to membrane receptors: cannot enter cells (direct contrast of steroid hormones) Synthesis, Packaging & Release -mRNA translates protein = “preprohormone” -> Enters ER to be modiFed = “prohormone” -> Travels via vesicle to Golgi: modiFes & cuts it -> Active hormone + peptide fragment inside secretory vesicle = Exocytosis releases hormone into EC± Ex. Processing: Insulin Proinsulin --> Insulin (active and can be metabolized by tissues) + C peptide - To measure lvls of insulin produced by tissues, cannot measure insulin b/c so quickly metabolized = measure lvls of C peptides (present in 1:1 ratio w/ insulin) Endocrine cells directly sense stimuli, then secrete hormone Stimuli: metabolite, hormone, neurohormone, neurotransmitter; i.e. glucose Endocrine cell: pancreatic beta cell Hormone released: Insulin PSL302: Lecture 03, by Prof. Lam ±riday, Sept. 17, 2010
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03 Classification of Hormones - PSL302: Lecture 03, by...

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