1. Chase Findley, MSIV

2. Vitamins, Fat Soluble, 94  Vitamins A, D, E, K Absorption dependent on ileum and pancreas Absorption dependent on ileum and pancreas Accumulate in body fat, more potential for toxicity Accumulate in body fat, more potential for toxicity Fat malabsorption conditions may cause deficiency Fat malabsorption conditions may cause deficiency ○ Cystic fibrosis, celiac sprue, mineral oil intake

3. Vitamins, Fat Soluble, 94  Vitamin A (Retinol) Found: liver, leafy vegetables Found: liver, leafy vegetables Functions: antioxidant, constituent of retinal visual pigment Functions: antioxidant, constituent of retinal visual pigment Deficiency: night blindness, dry skin Deficiency: night blindness, dry skin Excess: head ache, arthralgias, fatigue, skin changes, sore throat, alopecia Excess: head ache, arthralgias, fatigue, skin changes, sore throat, alopecia Teratogenic: cleft palate, cardiac problems Teratogenic: cleft palate, cardiac problems Remember bear hunter who eats liver! Remember bear hunter who eats liver!

4. Vitamins, Fat Soluble, 97  Vitamin D Found: Fortified milk Found: Fortified milk Function: Increases intestinal absorption of calcium and phosphate, bone resorption Function: Increases intestinal absorption of calcium and phosphate, bone resorption Deficiency: Rickets (children), osteomalacia (adults), hypocalcemic tetany Deficiency: Rickets (children), osteomalacia (adults), hypocalcemic tetany Excess: Hypercalcemia, hypercalciuria, loss of appetite, stupor. (Seen in sarcoidosis) Excess: Hypercalcemia, hypercalciuria, loss of appetite, stupor. (Seen in sarcoidosis)

5. Vitamins, Fat Soluble, 97  Vitamin D, continued D2 D2 ○ Found in plants, pharmacological form D3 D3 ○ Found in milk, formed in sun exposed skin 25-OH D3 25-OH D3 ○ Storage form 1,25-(OH)2D3 (Calcitriol) 1,25-(OH)2D3 (Calcitriol) ○ Active form

6. Vitamins, Fat Soluble, 97  Vitamin E Found: Vegetable oils, nuts, leafy vegetables Found: Vegetable oils, nuts, leafy vegetables Function: Antioxidant, protects RBC’s and membranes from free radical damage Function: Antioxidant, protects RBC’s and membranes from free radical damage Deficiency: Increased fragility of RBC’s, muscle weakness, neurodysfunction Deficiency: Increased fragility of RBC’s, muscle weakness, neurodysfunction

7. Vitamins, Fat Soluble, 98  Vitamin K Found: Leafy vegetables, some fruits Found: Leafy vegetables, some fruits Function: Necessary for synthesis of clotting factors II, VII, IX, X, protein C and S, catalyzes γ-carboxylation of glutamic acid residues Function: Necessary for synthesis of clotting factors II, VII, IX, X, protein C and S, catalyzes γ-carboxylation of glutamic acid residues Deficiency: Hemorrhage with increased PT, PTT, normal bleeding time. Deficiency: Hemorrhage with increased PT, PTT, normal bleeding time. ○ Neonatal hemorrhage, give Vitamin K at birth ○ Warfarin antagonizes Vitamin K

8. Vitamins, Water Soluble, 94  Vitamins B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 pyridoxine, B12 (cobalamin), C (ascorbic acid, biotin, folate  All except B12 and folate wash out from body, low risk of toxicity

9. Vitamins, Water Soluble, 94  Vitamin B1 (thiamine) Function: Component of thiamine pyrophosphate, cofactor in: Function: Component of thiamine pyrophosphate, cofactor in: ○ Pyruvate dehydrogenase (glycolysis) ○ α-ketoglutarate dehydrogenase (TCA cycle) ○ Transketolase (HMP shunt) ○ Branched chain amino acid dehydrogenase

10. Vitamins, Water Soluble, 95  Vitamin B1 (thiamine), continued Deficiency: Deficiency: ○ Wernike-Korsakoff syndrome Seen in malnutrition, alcoholism Seen in malnutrition, alcoholism Confusion, ophthalmoplegia, confabulation Confusion, ophthalmoplegia, confabulation ○ Beriberi (dry) Polyneuritis, symmetrical muscle wasting Polyneuritis, symmetrical muscle wasting ○ Beriberi (wet) High-output cardiac failure (dilated cardiomyopathy) edema High-output cardiac failure (dilated cardiomyopathy) edema

11. Vitamins, Water Soluble, 95  Vitamin B2 (riboflavin) Function: Cofactor in oxidation and reduction (FAD, FMN) B2=2 ATP Function: Cofactor in oxidation and reduction (FAD, FMN) B2=2 ATP Deficiency: Cheilosis, corneal vascularization Deficiency: Cheilosis, corneal vascularization

12. Vitamins, Water Soluble, 95  Vitamin B3 (niacin) Function: Constituent of NAD, NADP, used in redox reactions, B3=3 ATP Function: Constituent of NAD, NADP, used in redox reactions, B3=3 ATP Derived from tryptophan, requires B6 for synthesis Derived from tryptophan, requires B6 for synthesis Deficiency: Pellagra (diarrhea, dermatitis, dementia), glossitis Deficiency: Pellagra (diarrhea, dermatitis, dementia), glossitis ○ Hartnup disease (decreased tryptophan absorption) ○ Malignant carcinoid syndrome (increased tryptophan metabolism ○ INH (anti-TB) (decreased B6)

13. Vitamins, Water Soluble, 95  Vitamin B3 (niacin), continued Clinical use: Treatment of hyperlipidemia (decrease LDL, increase HDL) Clinical use: Treatment of hyperlipidemia (decrease LDL, increase HDL) Excess: Facial flushing, treat with aspirin Excess: Facial flushing, treat with aspirin

14. Vitamins, Water Soluble, 95  Vitamin B5 (pantothenate) Function: Component of CoA (cofactor in acyl transfers) and fatty acid synthase Function: Component of CoA (cofactor in acyl transfers) and fatty acid synthase Deficiency: Dermatitis, enteritis, alopecia, adrenal insufficiency Deficiency: Dermatitis, enteritis, alopecia, adrenal insufficiency

15. Vitamins, Water Soluble, 95  Vitamin B6 (pyridoxine) Function: Converted to pyridoxal, phosphate, cofactor in transamination (ALT/AST), decarboxylation reactions, glycogen phosphorylase, heme synthesis Function: Converted to pyridoxal, phosphate, cofactor in transamination (ALT/AST), decarboxylation reactions, glycogen phosphorylase, heme synthesis Required for synthesis of B3 (niacin) Required for synthesis of B3 (niacin) Deficiency: Convulsions, hyperirritability, peripheral neuropathy Deficiency: Convulsions, hyperirritability, peripheral neuropathy ○ May be induced by INH, OCP’s

16. Vitamins, Water Soluble, 96  Vitamin B12 (cobalamin) Found: Only in animal products, synthesized by microorganisms (large reserves in liver) Found: Only in animal products, synthesized by microorganisms (large reserves in liver) Function: Cofactor for homocysteine methyltransferase (transfers CH3 groups) and methylmalonyl-CoA mutase Function: Cofactor for homocysteine methyltransferase (transfers CH3 groups) and methylmalonyl-CoA mutase

17. Vitamins, Water Soluble, 96  Vitamin B12 (cobalamin) Deficiency: Deficiency: ○ Macrocytic-megaloblastic anemia ○ Neurological symptoms Irreversible if prolonged Irreversible if prolonged Paresthesias Paresthesias Sub acute combined degeneration Sub acute combined degeneration -Posterior and lateral spinal columns

18. Vitamins, Water Soluble, 96  Vitamin B12 (cobalamin) Causes of deficiency Causes of deficiency ○ Intestinal malabsorption Sprue, enteritis, fish tapeworm Sprue, enteritis, fish tapeworm ○ Lack of intrinsic factor Pernicious anemia Pernicious anemia ○ Absence of terminal ileum Crohn’s disease, surgical Crohn’s disease, surgical Schilling test to detect etiology of deficiency Schilling test to detect etiology of deficiency

19. Vitamins, Water Soluble, 96  Folic Acid Function: Converted to tetrahydrofolate (THF), coenzyme used in 1-carbon transfer/methylation reaction. Used in synthesis of nitrogenous bases in DNA/RNA Function: Converted to tetrahydrofolate (THF), coenzyme used in 1-carbon transfer/methylation reaction. Used in synthesis of nitrogenous bases in DNA/RNA Deficiency: Deficiency: ○ Macrocytic-megaloblastic anemia Without neurological symptoms Without neurological symptoms ○ Neural tube defects Prevent with prenatal supplements Prevent with prenatal supplements

20. Vitamins, Water Soluble, 96  Folic acid, continued Deficiency Deficiency ○ Much smaller liver stores than B12 ○ Most common US vitamin deficiency Especially in pregnancy, alcoholism Especially in pregnancy, alcoholism ○ Can be caused by phenytoin, sulfonamides, methotrexate

21. Vitamins, Water Soluble, 97  Biotin Function: Cofactor for carboxylation enzymes, pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase Function: Cofactor for carboxylation enzymes, pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase Avidin (raw egg whites) binds biotin and prevents absorption Avidin (raw egg whites) binds biotin and prevents absorption Deficiency: Dermatitis, alopecia, enteritis. Deficiency: Dermatitis, alopecia, enteritis. ○ Antibiotic use or excessive raw eggs

22. Vitamins, Water Soluble, 97  Vitamin C (ascorbic acid) Found: Fruits, vegetables Found: Fruits, vegetables Function: Antioxidant, also: Function: Antioxidant, also: ○ Facilitates iron absorption by keeping Fe in more absorbable Fe2+ ○ Necessary for hydroxylation of proline and lysine in collagen synthesis ○ Necessary for dopamine β-hydroxylase (converts dopamine to norepinephrine)

23. Vitamins, Water Soluble, 97  Vitamin C (ascorbic acid) Deficiency: Scurvy Deficiency: Scurvy ○ Swollen gums, bruising, anemia, poor wound healing

24. Minerals, 98  Zinc Function: Involved in activity of 100+ enzymes. Important in zinc finger (transcription factor motif) Function: Involved in activity of 100+ enzymes. Important in zinc finger (transcription factor motif) Deficiency: Delayed wound healing, hypogonadism, decreased adult hair, predisposes to alcoholic cirrhosis Deficiency: Delayed wound healing, hypogonadism, decreased adult hair, predisposes to alcoholic cirrhosis

25. Malnutrition, 98  Kwashiorkor Protein deficiency Protein deficiency Skin lesions, liver malfunction (fatty change), edema, anemia Skin lesions, liver malfunction (fatty change), edema, anemia

26. Malnutrition, 98  Marasmus Total calorie deficiency Total calorie deficiency Tissue and muscle wasting, loss of subcutaneous fat, edema Tissue and muscle wasting, loss of subcutaneous fat, edema

27. Ethanol Metabolism, 98  Alcohol dehydrogenase operates via zero-order kinetics  NAD+ is limiting reagent  Fomepizole inhibits alcohol dehydrogenase  Disulfiram inhibits acetaldehyde dehydrogenase

28. Universal Electron Acceptors, 101  NAD+, NADP+ Require Vitamin B3 (niacin) for production NAD+ ○ Catabolic processes, carry reducing equivalents as NADH NADP+ ○ Anabolic processes, supply reducing equivalents as NADPH ○ NADPH also used in respiratory burst, P-450  FAD+ Requires Vitamin B2 (riboflavin) for production

29. Metabolism, 101  ATP Production (Glycolysis) Hydrolysis drives energetically unfavorable reactions Aerobic metabolism ○ Produces 32 (heart/liver) 30 (muscle) ATP per glucose Anaerobic metabolism ○ Produces 2 ATP per glucose

30. Hexokinase Vs. Glucokinase, 101  First step of glycolysis is glucose to G6P  Reaction catalyzed by hexokinase or glucokinase, 1 st regulation point  Hexokinase Ubiquitous, high affinity (low Km), low capacity (low Vmax), feedback inhibited by product Ubiquitous, high affinity (low Km), low capacity (low Vmax), feedback inhibited by product  Glucokinase Liver and pancreas β-cells, low affinity (high Km) and high capacity (high Vmax) induced by insulin, sequesters excess glucose in liver. Liver and pancreas β-cells, low affinity (high Km) and high capacity (high Vmax) induced by insulin, sequesters excess glucose in liver.

31. Hexokinase Vs. Glucokinase, 101

32. Glycolytic Enzyme Deficiency, 103  Deficiency of pyruvate kinase or phosphoglucose isomerase  Inability to maintain Na+-K+ ATPase  RBC swelling, lysis  Hemolytic anemia RBC’s depend solely on glycolysis of glucose for metabolism RBC’s depend solely on glycolysis of glucose for metabolism

33. Pyruvate dehydrogenase Deficiency, 103  Back up of substrate (pyruvate, alanine), leads to lactic acidosis  Congenital and acquired (B1 deficiency) forms  Neurologic deficits  Treat by increasing intake of ketogenic nutrients (high fat, lysine, leucine)

34. Pyruvate Metabolism, 103 Alanine carries AA to liver from muscle Oxaloacetate used to in TCA cycle or gluco- neogenesis Transition from glyco- lysis to TCA cycle End of anaerobic glycolysis

35. Cori Cycle, 103  Muscle and RBC’s generate lactate via anaerobic glycolysis  Lactate sent to liver to be used in gluconeogenesis  Glucose can then be sent back and used by muscle and RBC’s  Loss of 4 ATP/Cycle

36. HMP Shunt, 105 Produces NADPH for fatty acid and steroid synthesis, and glutathione reduction in RBC’s Oxidative (irreversible) and non-oxidative and non-oxidative (reversible) phases Occurs in lactating mammary glands, liver, adrenal cortex, RBC’s

37. Respiratory Burst, 105  Produces reactive oxygen (HOCl) species for immune response  Occurs in neutrophils, macrophages  Involves membrane-bound NADPH oxidase (deficient in chronic granulomatous disease)

38. Glucose-6-Phosphate Dehydrogenase Deficiency, 106  G6PD produces NADPH, necessary to keep glutathione reduced, which detoxifies free radicals/peroxides  Decreased NADPH leads to hemolytic anemia due to damage from oxidizing agents  X-linked recessive, most common enzyme deficiency

39. Glucose-6-Phosphate Dehydrogenase Deficiency, 106  Oxidizing agents include fava beans, sulfanamides, primaquine, anti-TB drugs  Affected individuals have malarial resistance  Heinz bodies Altered precipitated hemoglobin in RBC’s Altered precipitated hemoglobin in RBC’s  Bite Cells From phagocytic removal of Heinz bodies by spleen From phagocytic removal of Heinz bodies by spleen

40. Glucose-6-Phoshate Dehydrogenase Deficiency, 106  Heinz bodies, bite cells

41. Disorders of Fructose Metabolism, 106  Fructose intolerance Hereditary deficiency of aldolase B Hereditary deficiency of aldolase B Autosomal recessive Autosomal recessive Fructose-1-phosphate accumulates, leading to decrease in available phosphate, inhibits glycogenolysis and gluconeogenesis Fructose-1-phosphate accumulates, leading to decrease in available phosphate, inhibits glycogenolysis and gluconeogenesis Hypoglycemia, jaundice, cirrhosis, Hypoglycemia, jaundice, cirrhosis,vomiting Decrease intake of fructose and Decrease intake of fructose andsucrose

42. Disorders of Fructose Metabolism, 106  Essential fructosuria Defect in fructokinase Defect in fructokinase Autosomal recessive Autosomal recessive Benign, asymptomatic Benign, asymptomatic Fructose in blood and urine Fructose in blood and urine

43. Disorders of Galactose Metabolism, 107  Classic galactosemia Absence of galactose-1-phosphate uridyltransferase. Absence of galactose-1-phosphate uridyltransferase. Autosomal recessive Autosomal recessive Toxic damage from galactitol Toxic damage from galactitol Failure to thrive, jaundice, Failure to thrive, jaundice, hepatomegaly, infantile cataracts, mental retardation Exclude galactose and lactose Exclude galactose and lactose from diet

44. Disorders of Galactose Metabolism, 107  Galactokinase deficiency Autosomal recessive Autosomal recessive Galactitol accumulates if galactose is present in diet Galactitol accumulates if galactose is present in diet Galactose appears in blood Galactose appears in blood and urine, infantile cataracts, and urine, infantile cataracts, failure to track objects, lack of social smile

45. Lactase Deficiency, 107  Age dependent or hereditary lactose intolerance due to loss of brush-border enzyme  Bloating, cramps, osmotic diarrhea  Avoid dairy products, lactase supplements

46. Transport of alanine and glutamine, 108  Glucose in muscle is oxidized to pyruvate, producing energy  Pyruvate is transaminated to alanine, travels to liver, providing nitrogen for urea cycle, and carbon for gluconeogenesis

47. Hyperammonemia, 108  Acquired (liver disease) or hereditary (urea enzyme deficiencies)  Results in excess NH4+, depletes α- ketoglutarate, inhibits TCA cycle  Tremor, slurring speech, somnolence, vomiting, cerebral edema, blurred vision  Treat with benzoate, phenylbutyrate

48. Ornithine Transcarbamoylase Defiency, 108  Most common urea cycle disorder  X-linked recessive  Interferes with elimination of ammonia  May present in first days of life  Excess carbamoyl phosphate converted to orotic acid  Orotic acid in blood and urine, decreased BUN, hyperammonemia

49. Phenylketonuria, 109  Decreased phenylalanine hydroxylase or tetrahydrobiopterin cofactor.  Tyrosine can not be synthesized, becomes essential  Autosomal recessive  Increased phenylalanine leads to excess phenylketones in urine.

50. Phenylketonuria, 109  Mental retardation, growth retardation, seizures, fair skin, eczema, musty body odor  Treat by increased tyrosine and decreased phenylalanine in diet  Maternal PKU, (deficiency in pregnancy) causes mental retardation, growth retardation, microcephaly, heart defects

51. Alkaptonuria, 109  Congenital deficiency of homogentisic acid oxidase in degradative pathway of tyrosine  Autosomal recessive  Dark connective tissue, pigmented sclera, urine turns black on standing, arthralgias

52. Albinism, 109  Congenital defect in either: Tyrosinase Tyrosinase ○ Inability to synthesize melanin from tyrosine ○ Autosomal recessive Tyrosine transporters Tyrosine transporters ○ Variable inheritance, locus heterogenity ○ Decreased availability of tyrosine for melanin synthesis

53. Albinism, 109  Can result from lack of migration of neural crest cells.  Increased risk of skin cancer

54. Homocystinuria, 100  Autosomal recessive  3 forms, all result in excess homocysteine  1. Cystathionine synthase deficiency  2. Decreased affinity of cystathionine synthase for pyridoxal phosphate (treat with increased B6 in diet)  3. Homocysteine methyltransferase deficiency

55. Homocystinuria, 110  Cystine becomes essential  Increased homocysteine in urine, mental retardation, osteoporosis, tall stature, kyphosis, lens subluxation, atherosclerosis (MI and stroke)

56. Cystinuria, 110  Hereditary defect of renal tubular amino acid transporter for cysteine, ornithine, lysine, arginine in proximal convoluted tubule.  Excess cystine in precipitates, forms cystine kidney stones.  Autosomal recessive  Treat with acetazolamide to alkalinize urine.

57. Maple Syrup Disease, 110  Blocked degradation of branched amino acids (Ile, Leu, Val)  Blocked degradation of branched amino acids (Ile, Leu, Val), due to decreased α- ketoacid dehydrogenase.  Results in accumulation of α-ketoacids in blood  Severe CNS defects, mental retardation, death.  Urine smells like maple syrup

58. Adenosine Deaminase Deficiency, 111  Excess ATP and dATP imbalances nucleotide pool (feedback inhibition of ribonucleotide reductase)  Prevents DNA synthesis  Decreased lymphocyte count  Major cause of severe combined immunodeficiency disorder

59. Lesch-Nyhan Syndrome, 111  Absence of HGPRT leads to defective purine salvage pathway  Excess uric acid production  X-linked recessive  Mental retardation, self-mutilation, aggression, hyperuricemia, gout, choreoathetosis

60. Orotic aciduria, 111  Inability to convert orotic acid UMP in de novo pyrimidine synthesis pathway Defect in orotic acid phosphoribosetransferase or orotidine 5’- phosphate decarboxylase  Autosomal recessive  Increased orotic acid in urine, megaloblastic anemia, failure to thrive  Treat with oral uridine

61. Insulin, 112  Synthesized in pancreas β cells  Released in response to ATP from glucose metabolism (depolarizing K+ channels)  Anabolic effects: Increases glucose transport, glycogen synthesis and storage, triglyceride synthesis and storage, protein synthesis Increased Na+ retention, cellular K+ uptake

62. Insulin, 112  Inhibits glucagon release by pancreas α cells  Insulin dephosphorylates  Serum C-peptide only present with endogenous protein Lack of C-peptide indicated exogenous insulin use Lack of C-peptide indicated exogenous insulin use

63. Insulin, 112  Insulin moves glucose into cells  Some cells do not need insulin, use a glucose transporter GLUT1: RBC’s, brain GLUT2: β islet cells, liver, kidney GLUT4: (insulin sensitive) adipose tissue, skeletal muscle

64. Glycogen, 112  Branches: α (1,6) bonds  Linkages: α (1,4) bonds  Glycogen phosphorylates  Skeletal muscle Glycogen undergoes glycogenolysis to form glucose, which is metabolized during exercise Glycogen undergoes glycogenolysis to form glucose, which is metabolized during exercise  Hepatocytes Glycogen is stored and undergoes glycogenolysis to maintain blood glucose levels Glycogen is stored and undergoes glycogenolysis to maintain blood glucose levels

65. Glycogen Storage Disease, 113 DiseaseFindingsDeficient enzyme Von Gierke’s (I)Severe fasting hypoglycemia, increased glycogen in liver, increased blood lactate, hepatomegaly Glucose-6-phosphate Pompe’s (II)CardiomegalyLysosomal α-1,4 glucosidase (acid maltase) Cori’s (III)Milder type I, normal blood lactate levels Debranching enzyme McArdle’s (V)Increased glycogen in muscle, muscle cramps, myoglobinuria Skeletal muscle glycogen phosphorylase All cause abnormal glycogen metabolism and accumulation within cells

66. Ketone Bodies, 115  In liver, fatty acids and amino acids are metobolized to acetoacetate and β- hydroxybutyrate for use in muscle and brain  Produced in response to starvation, alcoholism  Breath smells like acetone

67. Metabolic Fuel Use, 116  Exercise 1 st (seconds) Stored ATP, creatine phosphate, anaerobic glycolysis 1 st (seconds) Stored ATP, creatine phosphate, anaerobic glycolysis 2 nd (minutes) +Oxidative phosphorylation 2 nd (minutes) +Oxidative phosphorylation 3 rd (hours) Glycogen and FFA oxidation, glucose conserved 3 rd (hours) Glycogen and FFA oxidation, glucose conserved

68. Metabolic Fuel Use, 116  Fasting and starvation Preserve glucose for brain and RBC’s Preserve glucose for brain and RBC’s Days 1-3 Days 1-3 ○ Hepatic glycogenolysis and glucose release ○ Adipose release of free fatty acids, used by muscle and liver (in place of glucose) ○ Hepatic gluconeogenesis from peripheral lactate and alanine, adipose tissue

69. Metabolic Fuel Use, 116  Fasting and starvation After 3 days After 3 days ○ Muscle protein used for hepatic formation of ketone bodies for brain and heart Several days Several days ○ Ketone bodies become main energy source for brain ○ Survival time determined by fat stores

70. Lipid Transport Enzymes, 117  Pancreatic lipase Degradation of dietary lipase in small intestine Degradation of dietary lipase in small intestine  Lipoprotein lipase Degradation of TG in chylomicrons and VLDL Degradation of TG in chylomicrons and VLDL  Hepatic TG lipase Degradation of TG in IDL Degradation of TG in IDL  Hormone sensitive lipase Degradation of TG in adipocytes Degradation of TG in adipocytes

71. Cholesterol Synthesis, 116  Rate limiting step catalyzed by HMG-CoA reductase Enzyme inhibited by statins  2/3 plasma cholesterol is esterified by lecithin- cholesterol acyltransferase (LCAT)  Cholesterol ester transport protein (CETP) mediates transfer of cholesterol esters to lipoprotein particles

72. Essential Fatty Acids, 116  Can not be synthesized, must be in diet  Linoleic and linolenic acids  Arachidonic acid, if linoleic acid is absent  Necessary for synthesis of eicosandoids

73. Lipoprotein Functions, 118  Lipoproteins are composed of varying proportions of cholesterol, triglycerides, phospholipids  LDL transports cholesterol from liver to tissues  HDL transports cholesterol from tissues to liver

74. Lipoprotein Functions, 118  Chylomicron Delivers dietary TG’s to tissue Delivers cholesterol to liver as chylomicron remnants (depleted of triacylglycerols) Secreted by intestinal epithelial cells B-48, A-IV, C-II, E Familial dyslipidemia I ○ Increased chylomicrons ○ Elevated TG, cholesterol ○ Lipoprotein lipase deficiency or altered apolipoprotein C-II

75. Lipoprotein, 118  VLDL Delivers hepatic TG’s to tissue Delivers hepatic TG’s to tissue Secreted by liver Secreted by liver B-100, C-II, E B-100, C-II, E Hypertriglyceridemia Hypertriglyceridemia ○ Increased VLDL ○ Elevated TG ○ Hepatic overproduction of VLDL  IDL Formed by degradation of VLDL Formed by degradation of VLDL Delivers TG’s and cholesterol to liver, degraded to LDL’s Delivers TG’s and cholesterol to liver, degraded to LDL’s B-100, E B-100, E

76. Lipoprotein Functions, 118  LDL Delivers hepatic cholesterol to tissues Delivers hepatic cholesterol to tissues Formed by lipoprotein lipase modification of VLDL in tissue Formed by lipoprotein lipase modification of VLDL in tissue Taken up by target cells via receptor-mediated endocytosis Taken up by target cells via receptor-mediated endocytosis B-100 B-100 Familial dyslipidemia IIa Familial dyslipidemia IIa ○ Increased LDL ○ Elevated cholesterol ○ Autosomal dominant, absent/decreased LDL receptor

77. Lipoprotein Functions, 118  HDL Mediates reverse cholesterol transport from tissues to liver. Mediates reverse cholesterol transport from tissues to liver. Repository of apoC and apoE Repository of apoC and apoE Secreted from liver and intestine Secreted from liver and intestine

78. Abetalipoproteinemia, 118  Hereditary inability to synthesize lipoproteins, because of deficiency in apoB-100 and apoB-48  Autosomal recessive, appears early in life  Failure to thrive, steatorrhea, acanthocytosis, ataxia, night blindness