Overview of Lipid Metabolism

Lipid metabolism includes lipolysis and lipogenesis.

In lipolysis, dietary triglycerides are converted into fatty acids and glycerol, producing ATPs through different biochemical pathways.

Glycerol is first converted into glyceraldehyde 3-phosphate and then into glucose when ATP in the cells is high; otherwise, it is directed toward pyruvic acid production.

Fatty acids initially undergo beta-oxidation in the mitochondrial matrix, creating acetyl CoA that enters the Krebs cycle.

Interestingly, in hepatocytes, acetyl CoA undergoes ketogenesis to produce acetoacetate and other ketone bodies that enter the bloodstream.

Some of this acetoacetate can also be used by some other cells, like heart muscles, to generate ATP.

Lipogenesis, or lipid synthesis, occurs within the liver and adipose cells through different pathways.

This process converts surplus dietary carbohydrates, proteins, and fats into glycerol or fatty acids.

These can either be stored as triglycerides or undergo further anabolic reactions to form other lipids, such as lipoproteins, phospholipids, and cholesterol.