9.2: 9.2-Mobilization of Triacylglycerols

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Lipolysis and Mobilization of Triacylglycerols

The preferred source of energy for the body is carbohydrates. However, the storage of carbohydrates in the body (glycogen) is depleted within a few hours. Afterward, lipids become the next source of energy. When the body storage of glycogen is depleted, the production of certain hormones stimulates the hydrolysis of lipids. Lipolysis is the metabolic pathway catalyzed by lipases through which lipid triglycerides are hydrolyzed into glycerol and three fatty acids. It usually occurs in fat adipocytes, as a response to high epinephrine and low insulin levels in the blood. The free fatty acids and glycerol are then released into the blood. This process is called mobilization of triacylglycerol or fats.

Fat Metabolism.jpg

Image adapted from original by Cruithne9 / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0). Wikimedia Commons.

Mobilized fatty acids in the blood are transported to the required tissue forming a lipoprotein complex with serum albumin protein. Serum albumin is produced by the liver and is the most abundant blood protein in mammals.

Sources

Lipolysis on Wikipedia. Retrieved Sept 27, 2020. Content adapted under Creative Commons Attribution-ShareAlike License.

Serum albumin on Wikipedia. Retrieved Sept 27, 2020. Content adapted under Creative Commons Attribution-ShareAlike License.