This document summarizes the process of lipolysis. Lipolysis is the breakdown of triglycerides stored in fat cells into fatty acids and glycerol. It occurs mainly in adipose tissue to release fatty acids for energy. Triglycerides are transported to tissues like adipose and muscle via lipoproteins. Hormones such as epinephrine activate hormone-sensitive lipase in adipose tissue to break down triglycerides into glycerol and fatty acids. Glycerol enters the bloodstream and is converted to glucose by the liver, while fatty acids bind to albumin for transport and are broken down in mitochondria to produce energy.

1. LIPOLYSIS
~ By Ebtisam Al-Thawab

2. It is the catabolic process leading to the
breakdown of triglycerides stored in fat cells
and release of fatty acids and glycerol
It occurs largely in adipose to release fatty
acids as a fuel . May also occur in muscle or
liver- smaller amounts of fatty acids are stored
.

3. fatty acids glycerol
Lipases (HSL)
VLDL
Hormones
stimulate
Tissue Liver

4. LIPOLYSIS PROCESS
 Triglycerides are transported through the blood to
appropriate tissues (adipose, muscle ) by lipoproteins
such as VLDL (Very-Low-Density-Lipoproteins ) .
 Hormones include : epinephrine, norepinephrine ,
Growth hormone and thyroid hormone Activate
Hormone-sensitive lipase (HSL) found in adipose
tissue .
 Triglycerides present on the VLDL undergo lipolysis
by the cellular lipases (HSL) of target tissues, which
yields glycerol and free fatty acids .

6. • The glycerol also enters the bloodstream
and is absorbed by the liver or
kidney where it is converted to glycerol by
the enzyme glycerol kinase.
• Hepatic glycerol 3-phosphate is converted
mostly into dihydroxy acetone phosphate
(DHAP) and then glyceraldehyde 3-
phosphate (GA3P) to rejoin the
glycolysis and gluconeogenesis

7. Mitochondrial Beta Oxidation
Fatty acids bind to albumin, in the blood for transport.
Enter mitochondria for β-oxidation to produce energy .

8. • This is simple Animation Explain Lipolysis Mechanism
• -
http://www.wiley.com/college/grosvenor/0470197587/animations/Animati
on_Lipid_Metabolism/Energy/media/content/met/anima/met4a/frameset.
htm
•
• References
• Vance, DE and Vance, JE (Eds.). 2008. Biochemistry of Lipids,
Lipoproteins, and Membranes. 5th edition. Oxford, UK: Elsevier.
• Baldwin, Kenneth David Sutherland; Brooks, George H.; Fahey, Thomas
D. (2005). Exercise physiology: human bioenergetics and its
applications. New York: McGraw-Hill
• Harper‘s Biochemistry, By Robert K. Sppleton and Lange,2000