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12 Cards in this Set
- Front
- Back
What is hormone sensitive lipase?
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It is the rate determining step of lipolysis that releases the 1st FA from the TAG. The other 2 FA can be removed by HSL or other less specific lipases
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What is the activated form of hormone sensitive lipase?
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Phosphorylated "a" form is active
Inactivated form is the "b" form |
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What is the terminology for activated vs. inactivated hormones?
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Activated is the "a" form for
1. hormone sensitive lipase 2. phophorylase kinase 3. glycogen phosphorylase |
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How does cortisol effect hormone sensitive lipase?
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It upregulates the the synthesis
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What is the role of epinephrine or glucagon?
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This initiates activation via a specific receptor of the hormone sensitive lipase
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What is lipolysis? The enzymes that carry it out?
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Mobilizes fats from TAG via
1. lipoprotein lipase 2. Pancreatic lipase |
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What are methylxanthines?
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Caffeine or theophylline - both of which inhibit phophodiesterase (break down of cAMP -> AMP)
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What is protein kinase A?
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1. This is the enzyme that phophorylates (activates) hormone sensitive lipase.
2. It is activated by cAMP 3. It utilizes ATP and produces AMP after phophorylating HSL |
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What is phosphodiesterase?
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This breaks down cAMP -> AMP
1. Inhibited by caffeine/theophylline 2. Promoted by insulin |
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What are the HSL activating substances?
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HSL-a
Epinephrine Glucagon cAMP Protein kinase A Caffeine Theophylline |
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What are the HSL INactivating substances?
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HSL-b
Insulin AMP Phosphodiesterase Protein phosphatase |
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How and what regulates Hormone Sensitive Lipase?
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Figure 1. Hormonal activation of triacylglycerol (hormone-sensitive) lipase. Phosphorylation brings about activation to HSL-a.
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