Vitamin E - Tocopherol

Question 1

origin of vit. E

Answer 1

plant oils, liver, egg, meat

Question 2

absorption of vit E in small intestines

Answer 2

by chylomicron to the liver to be stored (also stored in adipose tissue and membranes(the fat soluble part)

Question 3

how is vit E tp in blood to other tissues

Answer 3

lipoproteins out from liver

Question 4

excretion of vit E

Answer 4

oxidised and bound to glucuronic acid

Question 5

deficiency reason

Answer 5

1. decr. uptake 2. decr absorption (enteitis, impaired bile secretion, fat poor diet) 3. deficiency of selenium: glutation peroxidase activity decreases (free radical removal)

Question 6

animal with special vit. E dificiencies

Answer 6

rat poultry cattle

Question 7

deficiency in rat

Answer 7

production problems - tissue damage in testis and uterus

Question 8

deficiency in poultry

Answer 8

“crazy chicken disease” membrane damage in brain -> odema

Question 9

deficiency in cattle

Answer 9

“white muscle disease” - damage to mitochondrial inner membrane -> damaged intermed. metabolism -> heat is prod. instead of ATP, heat damage muscle fibers

Question 10

what is oxidative stress

Answer 10

Reactive Oxygen Species - inability of the body to neutralize (antioxidants) reactive intermediates

Question 11

reasons for oxidative stress

Answer 11

incr. production of ROS/RNS(nitrogen)/RCS(chloride) and/ decr. antioxidant defence

Question 12

oxidative stress leads to

Answer 12

DNA, proteins, membranes will be damages, so several acute and chronic diseases are caused

Question 13

reactive oxygen species examples

Answer 13

• *free radicals:** O2⁻(superoxide), •OH (hydroxyl radical)
• *non-free radicals:** hydrogen peroxide

Question 14

reactive nitrogen species examples

Answer 14

free radicals: NO (nitrogen monoxide, vasodilator), NO2 (nitric acid)

Question 15

reactive chloride species examples

Answer 15

non-free radicals: HOCl (hipochloric acid)

Question 16

sources of free radicals

Answer 16

environment: UV-light, radiation, cigarette smoke, ozone

• *body:** resp. chain e.g. CYP450 (inflammation, antimicrobial)
• normal - if too much/little antiox. →damage

Question 17

types of reactive molecules

Answer 17

physiological: will damage the body
unphysiological: no damage to the body

Question 18

what is damaged by free radicals, and how

Answer 18

• *membrane:** unsat. FA is attacked
• *DNA:** H-bonds are modified causing mutation
• *Proteins:** peptide bonds→ side chains are damaged

Question 19

how does antioxidants work|

Answer 19

• stops chain reactions stimulated by the reactive molecules
• enzymes
• H-donors: vit. E, Vit. C, glutathione, uric acid
  → their db will be attacked instead of the ones in the membrane