Triglycerides
The major lipids of the body
(triglycerides, cholesterol,
phospholipids and glycolipids) play a
variety of biologic roles.
They serve as:
•Source of fuel.
•Important component of cell
membranes and many cells structures.
• They provide stability to the cell membrane
and allow for transmembrane transport.
• They are transported through the blood
stream in the form of lipoprotein.
• Fatty Acids: The lipid building blocks.
• Fatty acids are composed of a chain of
methylene groups with a Carboxyl functional
group at one end.
Fatty acid
Glycerol or Glycerin
Glycerol is a trihydric
alcohol (containing three OH hydroxyl groups) that
can combine with up to
three fatty acids to form
monoglycerides,
diglycerides, and
triglycerides
Triglycerides
A triglyceride consists of a glycerol
and three fatty acids. It is the major
type of lipid used for energy storage
and it is found in droplets within the
cytoplasm. It is non-polar and
relatively insoluble.
Triglycerides structure:
• The source of TG in the body can be
either dietary or synthesized in liver
and other tissues.
• TG molecules allow the body to
compactly store long carbon
chains(FA) for energy that can be
used during fasting states between
meals.
• Normal values: 40 – 160 mg /dl.
• Usually, serum triglyceride concentration is
requested either in combination with total
cholesterol or as part of lipid panel
examination (total cholesterol, triglycerides,
HDL, LDL and VLDL determination) to estimate
the degree of risk for hyperlipoproteinemia,
coronary artery disease (CAD), heart disease
and stroke.
Clinical significance:
• Increase in serum TG are relatively non
specific.
•
•
in heart diseases, liver and renal
diseases.
as in hyperthyroidism.
Method for determination:
• Quantitative enzymatic method:
Principle:
TG +H2O LPL
glycerol + free FA.
Glycerol+ATP glycerol kinase G3P+ ADP
G3P+O₂ GPO
DAP+ H₂O₂
H₂O₂+4AAP+4-Chlorophenol POD Quinoneimine+2H2O