Lipotropic factors

Question 1

what are lipotropic factors

Answer 1

choline, inositol

- found in high amounts in membranes as part of leichitin and sphingomyelin

Question 2

choline synthesis: microbial, storage

Answer 2

in the liver:
serine -> ethanolamine -> choline
- no microbial synthesis
- no storage

Question 3

origin of choline

Answer 3

beef, egg yolk, liver, soya, peanuts

Question 4

uptake of choline

Answer 4

2/3rds from diet in metabolised by intestinal microbes

1/3rd from diet is absorbed

Question 5

excretion of choline

Answer 5

in form of triethylamine produced by microbes

Question 6

biochemical role of choline

Answer 6

1. lipotropic agent: remove and prevent fatty deposits in the liver
2. precursor of leichitin + sphingomyelin synthesis
3. methyl donator; in form of betaine: neutral, pos charged
4. acetylcholine synthesis

Question 7

deficiency of choline leads to

Answer 7

1. fatty liver
2. haemorrhagic liver degeneration
3. less acetylcholine
4. slow growth

Question 8

origin of inositol

Answer 8

grains: in this form all OH of inositol are esterified by phosphate -> phytic acid, can also have Ca²⁺ or Mg²⁺ bound, salts -> all are refered to as phytates, which act as P stores for the plant

Question 9

diet form of inositol

Answer 9

inositol is mainly found in phytate form

Question 10

absorption of inositol

Answer 10

as inositol: phytase is found in bacteria and grains, and degrade phytate to inositol

Question 11

synthesis, storage of inositol

Answer 11

• liver, kidney from glucose
• microbial synthesis
• no storage

Question 12

biochemical role of inositol

Answer 12

1. lipotropic agent
2. inositol phosphatides of membrane: reservoir of arachidonic acid -> release phospholipase A2 -> prostaglandin synthesis is dep on this
3. inositol triphosphate: second messenger, insulin signalling, e.g. Ca²⁺ release from ER

Question 13

deficiency of inositol, how, leads to

Answer 13

• mostly in experimental conditions
• fatty liver
• slow growth