Vitamin E

Question 1

what two classes is vitamin E divided into

Answer 1

1. tocopherols (saturated)

2. tocotrienols (unsaturated)

Question 2

what is the most biologically active form of vitamin E

Answer 2

RRR alpha-tocopherol (D-alpha-tocopherol)

Question 3

individuals on __ diets may inadvertently limit their vitamin E uptake

Answer 3

low-fat

Question 4

the in enterocyte, vitamin E is incorporated into ___ for transport through the lymphatic system ultimately reaching the circulation

Answer 4

chylomicrons

Question 5

______ remnants deliver vitamin E to the liver using receptor mediated endocytosis

Answer 5

chylomicron

Question 6

discrimination between the different vitamer forms of vitamin E does not occur during their absorption into the ______

Answer 6

small intestine or in their packaging into chylomicrons

Question 7

in the liver RRR-alpha-tocopherol is incorporated into ___ for transport to the extrahepatic tissues

Answer 7

VLDL’s

Question 8

a specific protein called _______ ,which is made in the liver, mediates the transfer of RRR-alpha-tocopherol into the VLDL’s

Answer 8

alpha-tocopherol transfer protein

Question 9

the liver will secrete the other forms of vitamin E into the ____ via bile

Answer 9

feces

Question 10

____ can interfere with the enzymes of vitamin K cycle

Answer 10

tocopherol quinone

Question 11

oxidation of the phytyl tail by W and beta-oxidation lead to products called

Answer 11

alpha-carboxyethyl-hydroxychroman (alpha-CEHC)

Question 12

high intakes of vitamin E can interfere with all other fat soluble vitamins like

Answer 12

beta-carotene

Question 13

vitamin E can block the regeneration of the reduced form of vitamin ___, and thereby interfering with blood coagulation

Answer 13

K

Question 14

why do some physicians recommend discontinuing vitamin E before surgery

Answer 14

risk of hemorrhaging

Question 15

what 3 routes does RRR-alpha-tocopherol get to extrahepatic tissues

Answer 15

1. LDL receptor mediated endocytosis
2. lipoprotein lipase mediated uptake from VLDLs
3. phospholipid transfer protein (PTP) facilitates vitamin E transfer from lipoproteins to cell phospholipid membrane

Question 16

within cytoplasm of the cell, vitamin E ca bind to a specific tocopherol binding protein called

Answer 16

adenosine triphosphate binding cassette A1 (ABC A1)

Question 17

tocopherol -> ___ -> tocopheroxyl radical

Answer 17

ascorbate glutathione or ubiquinone

Question 18

vitamin E can inhibit protein kinase C by

Answer 18

dephosphorylation via activation of a specific protein phosphatase (PP2A)

Question 19

how does vitamin E inhibit heard disease and stroke

Answer 19

1. decrease LDL oxidation and decrease macrophage uptake
2. decrease protein kinase C activity
3. decrease monocyte endothelial adhesion
4. decrease scavenger receptor expression: decrease oxidized LDL uptake
5. decrease alpha-tropomyosin expression: decrease smooth muscle hypertrophy
6. decrease monocyte SOD activity
7. increase NO production: increase arterial dilation
8. increase PGI2: decrease TXA2: increase vasodilation: decrease platelet aggregation
9. increase carboxyethyl-hydroxychroman CEHC: decrease blood pressure

Question 20

what 4 positive functions do tocotrienols have

Answer 20

1. suppress activity of HMG-CoA reductase: reduce cholesterol synth
2. increase HMG-CoA reductase degradation and decrease efficiency of translation of HMG-CoA reductase mRNA
3. suppressed tumor cell angiogenesis
4. prevent glutamate induced neurotoxicity (parkinsons and alzheimer’s)

Question 21

what are the three increasing apoptosis mechanisms of gamma-tocotrienol

Answer 21

1. increased pro-apoptotic BAX expression
2. decreased anti-apoptotic BCL-2 expression
3. decreased the oncogene Myc expression

Question 22

vitamin E is shown to reduce the incidence of prostate cancer

Answer 22

T

Question 23

there are no trials seen of vitamin E providing benefiting effects to those with parkinsons and alzheimers

Answer 23

T

Question 24

vitamin E when taken with food may prevent heart disease, but no evidence it is preventative when taken it as a supplement

Answer 24

T

Question 25

vitamin E decreases peoples chance with ischemic stroke

Answer 25

T