Triacylglycerol Metabolism
Start with the big picture
TAG synthesis takes place mainly in the liver, adipose tissue, and intestinal mucosa, using ER-localized enzymes. Glycerol-3-phosphate is acylated to form intermediates, and diacylglycerol acyltransferase (DGAT) catalyzes the final step. TAG is exported in VLDL from the liver or in chylomicrons from the intestine. At tissues, lipoprotein lipase (LPL) releases fatty acids for uptake. Stored TAG is mobilized through ATGL, hormone-sensitive lipase, and monoacylglycerol lipase. Insulin favors storage, whereas fasting or exercise promotes lipolysis. The topic also connects altered TAG handling with hyperchylomicronemia, hepatic fat accumulation, and ectopic lipid deposition, and distinguishes TAG metabolism from the subsequent β-oxidation of fatty acids.
What you'll learn
- Outline the main sites, substrates, and steps of TAG synthesis.
- Explain how hepatic and intestinal TAG are packaged for transport.
- Describe LPL-mediated TAG hydrolysis and tissue uptake.
- Compare hormonal regulation of TAG storage and mobilization.
- Relate disrupted TAG metabolism to selected clinical consequences.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
