triglyceride transport

Definition

Target type: biologicalprocess

The directed movement of triglyceride into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Triglycerides are important components of plant oils, animal fats and animal plasma lipoproteins. [GOC:BHF, GOC:rl]

Triglycerides (TGs) are the primary form of energy storage in the body. They are synthesized in the liver and small intestine and transported in the blood via lipoproteins, specifically very-low-density lipoproteins (VLDL). The process of TG transport can be broken down into the following steps:

1. **Synthesis and Packaging:** In the liver, fatty acids from dietary sources or de novo synthesis are combined with glycerol to form TGs. These TGs are then packaged into VLDL particles along with cholesterol, phospholipids, and apolipoproteins. Apolipoproteins are proteins that act as ligands for specific receptors on cells and play a crucial role in lipoprotein metabolism.

2. **Secretion from the Liver:** VLDL particles are secreted from the liver into the bloodstream. Once in the circulation, VLDL undergoes a series of modifications.

3. **Lipoprotein Lipase (LPL) Activity:** VLDL particles encounter lipoprotein lipase (LPL), an enzyme that resides on the surface of endothelial cells lining blood vessels. LPL hydrolyzes TGs in VLDL, releasing free fatty acids and glycerol. These products can then be taken up by tissues for energy production or re-esterification.

4. **Formation of Intermediate Density Lipoproteins (IDL):** As VLDL loses its TGs, it becomes smaller and denser, transitioning into intermediate density lipoproteins (IDL).

5. **IDL Metabolism:** IDL can either be taken up by the liver through receptor-mediated endocytosis or further metabolized by hepatic lipase (HL).

6. **Formation of Low-Density Lipoproteins (LDL):** IDL that is not taken up by the liver is further metabolized by HL, leading to the formation of low-density lipoproteins (LDL). LDL is the primary carrier of cholesterol in the blood.

7. **LDL Uptake:** LDL particles are taken up by cells through receptor-mediated endocytosis, providing cholesterol for various cellular processes.

8. **Chylomicron Transport:** Dietary TGs are absorbed in the small intestine and packaged into chylomicrons, a type of lipoprotein similar to VLDL. Chylomicrons enter the lymphatic system and eventually reach the bloodstream. They also undergo LPL activity, releasing fatty acids for uptake by various tissues.

9. **Chylomicron Remnants:** After TG hydrolysis, chylomicron remnants are taken up by the liver for further processing.

The transport of TGs is a complex and highly regulated process. It involves the coordinated action of various enzymes, proteins, and receptors. Disruptions in TG transport can contribute to various health problems, including atherosclerosis, obesity, and type 2 diabetes.'
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Proteins (2)

Compounds (23)