2. • Organic compound that composed of 17C atoms bonded together in the form of
four fused rings:
- Cyclohexane rings / phenanthrene (designated as rings A, B and C)
- Cyclopentane ring (the D ring).
• Steroid contains one or more OH groups-Sterol
• Sterols are structural lipids present in membranes of most eukaryotic cells
3.
4. It produced by the liver & we consume it from meat and dairy products
6. CHOLESTEROL
•It is insoluble in water & soluble in organic solvent such as chloroform, benzene,
ether.
•General formula-C27H46O.
•It containing a cyclopentanoperhydro phenanthrene.
•It has one OH group at C3 & a double bond b/w C5 & C6.
•An eight carbon aliphatic side chain is attached to C17.
7. •Methyl side chains at position C10 & C13.
•It is amphipathic in nature,
- Polar head the OH gp at C3
- non polar steroid nucleus & hydrocarbon side chain at C17
•It is major component of cell membranes & lipoprotein.
•It is found as associated with FA to form cholesterylesters.
8. Cholesterol Esters
• Excess cholesterol is stored as
cholesterol esters in cytosolic lipid
droplets
In total cholesterol :
• About 30% free form (un esterified)
70% - cholesteryl esters form
9. FATE
OF
CHOLESTEROL
Synthesis of Bile
Salts
Major component of
lipoproteins
Synthesis of
Steroid hormones
(Progesterone, Gluco &
Mineralocorticoids
Androgens & Estrogen)
Structural material
in biological
membranes
Decrease membrane
fluidity
Required for
synthesis of Vit- D
10. Bile acids & Bile salts
• Synthesized in the liver from cholesterol.
• Stored & concentrated in the gallbladder.
Bile acids:
Primary Bile Acids - Glyco & Tauro cholic acid
Glyco & Tauro chenodeoxycholic acid
Secondary Bile Acids- Deoxycholic Acid
Lithocholic acid
Bile salts: Na+ & K + glycocholic acid
Na + & K + Tauro chenodeoxy cholic acid
11. Functions
• They facilitate the digestion of dietary TG by acting as
emulsifying agents that render fats accessible to pancreatic lipases.
• Discharged into gut and aides in absorption of intra luminal lipids,
cholesterol, & fat soluble vitamins.
• Bile acids & phospholipids solubilize cholesterol in the bile, -
preventing the precipitation of cholesterol in the gallbladder.
14. Deposition of lipids in the inner
arterial wall.
Formation of plaque
Endothelial damage
Narrowing of the arterial lumen
Thickening or hardening of arteries
due to the accumulation of lipids &
cholesterol in the inner arterial wall.
15. Causes
Environmental factors - obesity and dietary choices.
Genetic factors – additive effects of multiple genes
single gene defect (case of familial hypercholesterolemia).
secondary causes :
High consumption alcohol & smoking
Type 2 Diabetes mellitus,
Nephrotic syndrome
Obstructive jaundice
Hypothyroidism
Cushing’s syndrome,
16. • It can control by
- Consumption of PUFA
- Dietary fiber
- Avoiding high carbohydrate diet
- Taking statin drugs (lavastatin, simvastatin & atorvastatin)
