Lecture_16_3-25-10-PDF_41130

Lecture_16_3-25-10-PDF_41130 - Lipid Metabolism (Lec 14-17)...

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5. Regulation of Fatty acid metabolism 6. Synthesis of other lipids A. Glycerophospholipids B. Sphingolipids C. Prostaglandins 7. Cholesterol Metabolism A. Cholesterol biosynthesis B. Regulation of Cholesterol Synthesis C. Cholesterol Transport and Atherosclerosis Lipid Metabolism (Lec 14-17) Lec16 Lec17
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5. Regulation of Fatty acid metabolism 6. Synthesis of other lipids A. Glycerophospholipids B. Sphingolipids C. Prostaglandins Lec16
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How Are Choices About Fatty Acid Metabolism Made? Fatty acids are a valuable fuel, and are burned ONLY when their energy is needed In the cytosol of liver cells, fatty acyl-CoA’s are either taken into mitochondria for b -oxidation or converted into TAGs and phospholipids by cytosolic enzymes This metabolic fork is governed by the rate of uptake of fatty acyl-CoA’s into mitochondria which can be inhibited by malonyl-CoA…
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When ATP demand is mitochondrial acetyl CoA can be stored as Fatty acids This occurs in the cytosol Under what conditions would the cell want to have abundant acetyl-CoA in the cytosol?
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Energy stores and inter-conversions in humans Adipocytes (fats) provide the major energy store in humans, but muscle proteins are also degraded when food intake is inadequate. These figures are for a 70kg male. MJ: MegaJoules. Typical daily energy intakes are about 12 MJ per day for males, 9.2 MJ for females 1 calorie (cal) = 4.1868 joule (J)
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adipose tissue ADP ATP CO 2 + H 2 O Heat Work or Growth Food fatty acids & triacyl- glcerols Regulation of Fatty acid metabolism
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adipose tissue ADP ATP CO 2 + H 2 O Heat Work or Growth Food fatty acids & triacyl- glcerols Obesity An imbalance between energy input and output can lead to ill, such as obesity
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Regulation of Fatty acid metabolism For a eukaryotic organism, fat synthesis and breakdown is paramount in the energy flow pathways. This is an interdependent network of systems connected by the blood stream. Chylomicrons and VLDLs circulate triacylclycerols and albumins bind and circulate fatty acids.
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Interrelationship of fat, muscle, liver, and brain During starvation, ketone bodies are synthesized in the liver from fatty acids and used as fuel by the brain and other organs instead of glucose.
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Model for plasma triacylglycerol and cholesterol transport in humans Chylomicrons are delipidated in the capillaries of peripheral tissues Then, tissues take up the free fatty acids Exogenous (From outside)
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Exogenous (From outside) Endogenous (From inside) VLDLs are degraded in the capillaries The released fatty acids are taken up by the adipose tissue and muscle Model for plasma triacylglycerol and cholesterol transport in humans
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Regulation of Fatty acid metabolism Glucagon , epinephrine and norepinephrine activate oxidation through a hormone-sensitive lipase . Increased cAMP levels activate PKA (protein kinase A, AKA cAMP-dependent kinase) and phosphorylation activates oxidation.
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This note was uploaded on 09/15/2010 for the course BCHS 3305 taught by Professor Fujita during the Spring '10 term at University of Houston.

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Lecture_16_3-25-10-PDF_41130 - Lipid Metabolism (Lec 14-17)...

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