Fat Soluble Vits

Question 1

General Info

Answer 1

Fat soluble vitamins are isoprenoids (repeats of isopentyl pyrophosphate). Building blocks for cholesterol. Fat malabsorption can lead to fat soluble vitamin problems. Fats are transported from intestines by chylomicrons.

Question 2

Vitamin A

Answer 2

Three forms = Retinal, Retinol, Retinoic Acid
Commonly found as retinol ester in animals and retinal in plants. Beta Carotene is oxygenated and cleaved into two retinals which are then converted into retinols

Transported by chylomicrons and retinol binding protein (instead of VLDL)

Question 3

Retinal

Answer 3

prosthetic group of rhodopsins. Retina uses it to sense light, upon light absorb it switches from cis to trans. Change in the way the molecule sits in the membrane is detected by opsin. This sends an action potential to brain.

Def = night blindness

Question 4

Retinoic Acid

Answer 4

acts as steroid hormone, essential for maintenance of epithelia and membranes, not directly involved in vision.

Deficiency = metaplasia (change in type of epithelia) from columnar to keratinized squamous epithelia cells. Essentially wet to dry. This leads to blindness.

Toxicity high lvls of Retinoic acid can be teratogenic

Question 5

Vitamin D

Answer 5

UVB is required to open up chol ring in the skin to form cholecaleiferol (D3). D3 goes to liver and then to kindey where it meets with PTH and gets converted to calcitrol (active vit D).
This is the only pathway where reg is by final step, calcium lvls. Calcitrol works together with PTH to increase plasma Ca lvls. can be used as osteoperosis treatment

Question 6

Vit D Def

Answer 6

Bone mass loss, Ricketts in youth, osteomalacia in old

Question 7

Vit D Tox

Answer 7

Hypercalcemia, hypercalcuria, metastatic calcification, renal and CV dmg

Question 8

Vitamin E

Answer 8

Alpha tocopherol family, believed to be an antioxidant. may be useful against oxidation of LDL to foam cells in artherosclerosis

Inhibits platelet aggregation

Question 9

Vit E Def

Answer 9

Mild hemolytic anemia

Question 10

Vitamin K

Answer 10

coagulation vitamin, used for clotting. First fat soluble vitamin to be def in fat malabsorb

Inhibited by warfarin

Question 11

Vit K def

Answer 11

hemorrhagic and most common neonate disease