We will review the role of triglyceride synthesis in ..
Fatty Acid Synthesis | Lipoprotein | Triglyceride
Figure 1. Major sources for hepatic lipids. This figure illustrates the origin of the triglyceride (a common form of fat) that is found in the liver in different physiological states. After a meal, the triglycerides obtained from the diet are modified in the intestine and exported to the bloodstream. Muscle and fat tissue can import and process the triglyceride molecules, modifying them according to their specific needs. The liver can also produce its own triglycerides from sugars and amino acids, in a process called lipogenesis (DNL). Within liver cells, the fat is metabolized in order to be stored in structures called lipid droplets (LDs) or to be exported to other organs via the bloodstream in association with particles called lipoproteins (in this case, very low density lipoprotein, VLDL). During fasting, the breakdown of triglyceride storage depots occurs, releasing fatty acids (the main breakdown products of triglycerides into the blood. When it reaches the liver, it can be used to provide energy through a process called fatty acid oxidation, or can be modified to produce VLDL. In the setting gf obesity or diabetes, the breakdown of triglyceride storage depots is stimulated and the synthesis of triglyceride in the liver increases. It results in the accumulation of triglyceride in the liver and increased levels in the blood, both of which are commonly observed in patients with a common condition known as nonalcoholic fatty liver disease.
Since triglyceride synthesis prevails ..
Figure 3. Hepatic triglyceride metabolism. This figure summarizes the cellular routes by FA are converted into more complex lipid forms, including triglycerides (TG). Mitochondrial proteins and those within the endoplasmic reticulum (GPAT, AGPAT, PAP, and DGAT) mediate a series of enzymatic reactions including addition of FA-derived intermediates and removal of a phosphate group, which culminates in the formation of TG. TG formed from FA that are synthesized within the liver cells are most likely exported to the bloodstream in VLDL for delivery to other organs. On the other hand, TG produced from FA that are delivered to the liver from the blood are destined for storage in the liver. Other enzymes (DGAT1 and DGAT2) may also regulate the differential usage of FAs.