LIPIDS AND LIPO Flashcards
petroleum industry
Lipoproteins
redistributing dietary and hepatic-synthesized
triglycerides to peripheral cells mostly during fasting for energy needs or
storage as fat.
The very-low-density lipoproteins (VLDLs)
rich in cholesterol, which
start out as VLDLs, are like nearly empty tankers that just deliver cholesterol
to peripheral cells and return to the liver after their main cargo, triglycerides,
have been off loaded.
low-density lipoproteins (LDLs)
are the cleanup
crew, gathering up excess cholesterol for transport back to the liver.
Cholesterol is used by the body for such useful functions as facilitating
triglyceride transport by lipoproteins and maintaining the normal structure
and integrity of cell membranes, and as a precursor for steroid hormone
synthesis, but when in excess, it can lead to cardiovascular disease.
high-density lipoproteins (HDLs)
-Commonly referred to as fats.
-composed of mostly carbon-hydrogen ( C-H )
bonds, they are a rich source of energy and an
efficient way for the body to store excess calories.
-Insoluble in blood and water, but soluble in
organic solvents
-Transported by lipoproteins , namely
triglycerides, phospholipids, cholesterol, and fat
soluble vitamins (ADEK)
LIPIDS
Linear chains of C-H bonds that terminate with a carboxyl group
(- COOH).
As to length can be classified as short-chain (4 to 6 carbon atoms),
medium-chain (8 to 12 carbon atoms), long-chain (12 to 18 carbon
atoms), or very-long-chain (>20 carbon atoms) fatty acids.
As to the number of C=C bonds, they can be saturated or unsaturated
Mostly found as constituents of phospholipids or triglycerides
Mainly derived from hydrolysis of triglycerides in adipose tissues
Small amount is present in plasma, most is bound to albumin.
Important source of energy
Provide the substance for conversion of glucose
Reference value: 9-15 mg/dl
FATTY ACIDS
Triacyglycerol (neutral fat)
3 molecule of fatty acid and one molecule of glycerol by ester bond
Hydrophobic and water soluble
Main storage of lipid in man ( adipose tissue) - 95% of stored fat and the predominant form
of glyceryl ester found in plasma
Breakdown of TAG are metabolized, their fatty acids are release to the cells and converted
into energy
Breakdown of TAG are facilitated by:
> lipoprotein
> lipase
> epinephrine
> cortisol
TRIGLYCERIDES
Fasting requirement for triglycerides
12-14 hours
Reference value for lipids
9-15 mg/dl
Reference value for triglycerides in Normal state
<150 mg/dl
Reference value for triglycerides in Borderline High
150-199 mg/dl
Reference value for triglycerides in High TAG
200-499 mg/dl
Reference value for triglycerides in Very High TAG
200-499 mg/dl
Chemical Methods
I. Colorimetric Method (Van Handel and Zilversmith)
II. Flourometric Method (Hantzsch Condensation)
Enzymatic Methods
major interference; normally present in plasma
concentration below 0.163 mmol/L, equivalent to 14 mg/dL TAG
concentration
Glycerol
Hydrolysis of TAG to free fatty acids and glycerol,
followed by the phosphorylation of glycerol to glycerophosphate
Glycerol Kinase Method
Involves alkaline
hydrolysis (saponification) using alcoholic KOH, solvent extraction with chloroform
and the extract is treated with silicic acid (chromatography) to isolate TAG and a
color reaction with chromotopic acid, giving rise to a pink end color
CDC reference method (Modified Van Handel and Zilversmith)
Increased Triglycerides BECAUSE OF
Hyperlipoproteinemia Types I,
IIb, III, IV, and V
Nephrotic syndrome
Alcoholism
Hypothyroidism
Pacreatitis