CBP

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Calcium absorption
CBP
Ca2
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Vitamin E and Selenium

• Bishop and Evans (1922) showed that diets
  containing purified sources of protein, fat,
  carbohydrate, and minerals would not support
  reproduction in rats. Yeast or lettuce restored
  fertility.

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Vitamin E and Selenium

• Bishop and Evans (1922) showed that diets
  containing purified sources of protein, fat,
  carbohydrate, and minerals would not support
  reproduction in rats. Yeast or lettuce restored
  fertility.
• Whole wheat prevented the problem and wheat germ
  oil was the location of the anti-sterility
  factor.

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Vitamin E and Selenium

• Bishop and Evans (1922) showed that diets
  containing purified sources of protein, fat,
  carbohydrate, and minerals would not support
  reproduction in rats. Yeast or lettuce restored
  fertility.
• Whole wheat prevented the problem and wheat germ
  oil was the location of the anti-sterility
  factor.
• Evans et al. (1936) isolated a-tocopherol from
  wheat germ oil and Fernholz (1938) confirmed the
  chemical structure.

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Vitamin E and Selenium

• Bishop and Evans (1922) showed that diets
  containing purified sources of protein, fat,
  carbohydrate, and minerals would not support
  reproduction in rats. Yeast or lettuce restored
  fertility.
• Evans et al. (1936) recognized that a group of
  compounds were involved and suggested the name
  tocopherol from tokos (greek) for offspring
  and phero to bear.
• Whole wheat prevented the problem and wheat germ
  oil was the location of the anti-sterility
  factor.
• Evans et al. (1936) isolated a-tocopherol from
  wheat germ oil and Fernholz (1938) confirmed the
  chemical structure.

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Vitamin E and Selenium

• Deficiency symptoms
• female rats sterility, fetal death
• testis degeneration
• nutritional encephalomalacia
• muscular dystrophy

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Vitamin E and Selenium

• Fernolz (1938) proposed the structural formula
  and the compound was synthesized (Karrer et al.
  1938).
• Different tocopherols have been isolated from
  different plant oils and the greek alphabet has
  been used to distinguish between the various
  forms
• alpha, beta, gamma
• Schwartz (1958) proposed that selenium would
  prevent liver necrosis associated with Vitamin E
  deficiency (rats) and Rotruck (1972) reported
  that Se was a component of glutathionine
  peroxidase.

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Absorption, Transport, and Distribution of
Vitamin E

• Vitamin E is the term for 8 natural occurring
  compounds
• four TOCOL structures with a saturated side
  chain
• four TOCOTRIENOL structures (3 double
  bonds)

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• The side chain facilitates the incorporation and
  retention of Vitamin E in biomembranes so the OH
  group is positioned optimally for scavenging free
  radicals and terminating lipid peroxidation.

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• The side chain facilitates the incorporation and
  retention of Vitamin E in biomembranes so the OH
  group is positioned optimally for scavenging free
  radicals and terminating lipid peroxidation.
• All cells exposed to molecular oxygen are at risk
  for being damaged by oxygen derived free radicals
  and lipid peroxidation products

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• The side chain facilitates the incorporation and
  retention of Vitamin E in biomembranes so the OH
  group is positioned optimally for scavenging free
  radicals and terminating lipid peroxidation.
• All cells exposed to molecular oxygen are at risk
  for being damaged by oxygen derived free radicals
  and lipid peroxidation products
• Complimentary antioxidant systems (superoxide
  dismutase, glutathionine peroxidase, catalase,
  ascorbate) all work in defending against
  oxidative damage.

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• Vitamin E is the most important lipid soluble
  antioxidant, it works to quench free radicals and
  terminate lipid peroxidation.

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• Vitamin E is the most important lipid soluble
  antioxidant, it works to quench free radicals and
  terminate lipid peroxidation.
• The Vitamin E radical is fairly stable, the
  unpaired electron on the oxygen atom can be
  delocalized into the aromatic ring structure,
  increasing stability.

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• Vitamin E is the most important lipid soluble
  antioxidant, it works to quench free radicals and
  terminate lipid peroxidation.
• The Vitamin E radical is fairly stable, the
  unpaired electron on the oxygen atom can be
  delocalized into the aromatic ring structure,
  increasing stability.
• The Vitamin E radical can be reduced back to
  Vitamin E by ascorbate and glutathione, the
  formation of alpha-tocopherol quinone or react
  with another Vitamin E radical to form a dimer.

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Antioxidant Activity

• 1. Initiation production of R (carbon
  centered radical)
• 2. Propagation R O2 ? ROO (fast)
• 3. ROO RH ? ROOH R (H atom abstraction)
• 4. Termination ROO ROO ? inactive products
• 5. Inhibition a-TOH ROO ? a-TO ROOH
• 6. a-TO ROO ? inactive products

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Vitamin E Activity

• The rate at which phenolic antioxidants react
  with peroxy radicals (reaction 5) is an indices
  of antioxidant efficiency.
• a-tocopherol reacts approximately 200 X faster
  with peroxyl radicals than does BHT (commercial
  antioxidant)
• The chroman head group is completely responsible
  for the antioxidant properties, the phytyl tail
  has no influence on antioxidant activity, it only
  allows for membrane solubility (plasma membranes)

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Vitamin A

• McCollum and Davis (1915) described a fat
  soluble A factor that had growth promoting
  activity, McCollum and Simmond (1917)
  demonstrated the factor prevented eye lesions
  (xerophthalmia).

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Vitamin A

• McCollum and Davis (1915) described a fat
  soluble A factor that had growth promoting
  activity, McCollum and Simmond (1917)
  demonstrated the factor prevented eye lesions
  (xerophthalmia).
• Steenbock et al (1919-1922) recognized a similar
  growth promoting factor in plants and Moore
  (1930) linked carotene and Vitamin A activity.

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Vitamin A contd

• Wolbach and Howe (1925)
• Tissue changes following deprivation of
  fat-soluble A
• Casein 18
• Starch 51
• Salt mixture 4
• Lard 24 (Control rats butter fat)
• Brewers yeast 3

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Vitamin A contd

• Wolbach and Howe (1925)
• Tissue changes following deprivation of
  fat-soluble A
• - tissue changes in epithelial tissues
• - substitution of stratified keratinizing
  epithelium for normal epithelium in various parts
  of the respiratory tract, alimentary tract, eyes,
  paraocular gland, genitourinary tract

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Vitamin A contd

• Wolbach and Howe (1925)
• Tissue changes following deprivation of
  fat-soluble A
• - tissue changes in epithelial tissues
• - substitution of stratified keratinizing
  epithelium for normal epithelium in various parts
  of the respiratory tract, alimentary tract, eyes,
  paraocular gland, genitourinary tract

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Vitamin A contd

• - young rats respond more promptly than adults
• - growth activity of the epithelium is not
  diminished
• - the replacement of epithelium arises from
  focal proliferation of cells arising from the
  original epithelium and not by differentiation or
  changes in pre-existing cells

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Vitamin A contd

• Vitamin A and Carotene
• Moore (1930) the first conclusive data
  showing the conversion of b-carotene to
• Vitamin A in animals

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Vitamin A contd

• Vitamin A esters are hydrolyzed in the lumen of
  the brush border and retinol in the intestinal
  cell is esterified to palmitate.

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Vitamin A contd

• Vitamin A esters are hydrolyzed in the lumen of
  the brush border and retinol in the intestinal
  cell is esterified to palmitate.
• Retinyl esters are transported to the liver via
  the lymphatic system.

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Vitamin A contd

• Vitamin A esters are hydrolyzed in the lumen of
  the brush border and retinol in the intestinal
  cell is esterified to palmitate.
• Retinyl esters are transported to the liver via
  the lymphatic system.
• Stored in the liver as the ester and mobilized
  by hydrolysis of the ester.

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Vitamin A contd

• Retinol binding protein (RBP) is synthesized by
  the liver and binds one more of retinol
  (functions to stabilize and solubilize retinol).
• There are specific binding proteins in the cell
  that bind either retinol (CRBP) or retinoic acid
  (CRABP)

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Vitamin A contd

• Retinoic Acid stimulates growth but does not
  correct other deficiency symptoms
• Vision visual cycle
• - deficiency results in lack of rhodopsin
• (protein- opsin 11-cis- retinal)
• retinol ? NADH ? 11-cis-retinal
• NAD
• 3 pigments (red, green, blue) all have 11-cis
  retinal

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Vitamin A contd

• Kertinatization (differentiation) of epithelial
  tissue
• mucous secreting cells cant synthesize mucous
• xerophthalmia eye lesion unrelated to visual
  cycle
• (glycoprotein synthesis)

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Vitamin A contd

• Kertinatization (differentiation) of epithelial
  tissue
• mucous secreting cells cant synthesize mucous
• xerophthalmia eye lesion unrelated to visual
  cycle
• (glycoprotein synthesis)
• Reproduction (may be related to epithelial
  effects)

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Vitamin A contd

• Kertinatization (differentiation) of epithelial
  tissue
• mucous secreting cells cant synthesize mucous
• xerophthalmia eye lesion unrelated to visual
  cycle
• (glycoprotein synthesis)
• Reproduction (may be related to epithelial
  effects)
• Bone defects decrease in osteoclastic activity
  and normal remodeling of bone

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Vitamin A contd

• Kertinatization (differentiation) of epithelial
  tissue
• mucous secreting cells cant synthesize mucous
• xerophthalmia eye lesion unrelated to visual
  cycle
• (glycoprotein synthesis)
• Reproduction (may be related to epithelial
  effects)
• Bone defects decrease in osteoclastic activity
  and normal remodeling of bone
• Reduced enzyme activity

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