Lipolysis (TG Mobilization) Flashcards
What is Lipolysis?
The breakdown of triglycerides stored in Adipose Tissue.
Triglycerides are broken down into what during Lipolysis?
Glycerol + Fatty Acids
When is Lipolysis driven (activated) in our body?
When there are low levels of glucose and/or insulin
What are the 3 primary enzymes of the Lipolysis Pathway?
ATGL (Adipose Triglyceride Lipase)
HSL (Hormone Sensitive Lipase)
MGL (MonoAcyl Glycerol Lipase)
What protein regulates the Lipolysis Pathway?
Perilipin-1A (countered to insulin)
How are the Fatty Acid Tails released from their Glycerol Backbone?
Through the cleaving of the Ester Bonds that bind the “fatty acid tails” to the “Glycerol backbone”
What is the process of Hydrolysis consist of?
Breaking bonds through a chemical reaction with water.
In the first step of Lipolysis, a Fatty Acid Tail is liberated from the Glycerol Backbone through what molecule?
H20
When a Fatty Acid Tail is liberated from the Glycerol Backbone, what does the Triglyceride turn into?
Diglyceride
What is the enzyme used in the hydrolysis of the first fatty acid tail liberated?
Adipose TG Lipase (ATGL)
In the process of liberating the 2nd fatty acid tail from a Diglyceride, what does the Diglyceride become?
Monoglyceride
What enzyme is utilized in the liberation of the 2nd Fatty Acid tail from the Diglyceride?
Hormone Sensitive Lipase (HSL)
When a Monoglyceride loses it’s final Fatty Acid Tail, what does it then become?
Glycerol
What enzyme is utilized in the liberation of the final Fatty Acid tail from the Monoglyceride?
Monoglyceride Lipase (MGL)
How many water molecules are required for Lipolysis?
3
What Hormones can trigger Lipolysis?
Adrenaline (Epi/NE)
Cortisol
Glucagon
What hormone inhibits Lipolysis?
Insulin (most potent anti-lipolytic agent in the body)
+ Ketones (fasting/starvation)
The products of Lipolysis (Free Fatty Acids, Glycerol, and Monoglycerides) move where once they are broken down from TG’s?
Into the cells (enterocytes) of Intestinal Epithelium
Once FFA, Glycerol, and Monoglycerides cross into the intestines, what do they do?
Reform into TG’s
Triglycerides + _______ are packaged in the enterocytes to form what?
TG + Cholesterol = Chylomicron (large lipoprotein particles)
Chylomicrons leave through where & do what?
Leave enterocytes > Into the Bloodstream > deliver Fats to tissues
What allows TG’s from Chylomicrons to pass through capillary walls & into tissues?
(LPL) Lipoprotein Lipase
Once TG’s make their way to tissues what do they do?
Either oxidize for energy or re-esterify for storage
During 1 round of Beta-Oxidation, how many carbons are stripped from a Fatty Acid & what is the yield?
2 carbons are stripped & 1 Acetyl-CoA molecule (for TCA cycle)
What is the total yield of a Fatty Acid (Carbon & Acetyl-CoA)?
16 Carbons & 8 Acetyl-CoA
What happens when Acetyl-CoA is produced in excess?
It is diverted to produce Ketone Bodies
