Lipid metabolism — Flashcards

Flashcard 21: Give the life cycle of LDL.

Answer: formed by modification of IDL in peripheral tissues, delivers cholesterol to peripheral tissues

Flashcard 22: Function of hormone-sensitive lipase (HSL)?

Answer: Degradation of TG (triacylglycerols) stored in adipocytes

Extra: Hormone-sensitive lipase (HSL) is activated by catecholamines and inhibited by insulin. It hydrolyzes stored triglycerides to provide free fatty acids for energy during fasting.

Flashcard 23: What is the primary function of Hepatic TG lipase (HL)?

Answer: Degradation of TG remaining in IDL and LDL (converts IDL to LDL)

Extra: Hepatic lipase (HL) or Hepatic TG lipase (HTGL) is found in the hepatic capillary endothelium and functions to clear remnant lipoproteins from circulation.

Flashcard 24: What is the function of lipoprotein lipase (LPL)?

Answer: Liberates fatty acids from triglycerides circulating in chylomicrons and VLDLs.

Extra: Synthesized and secreted by adipocytes and muscle cells; sits on the luminal surface of capillary endothelium (anchored by heparan sulfate). Activated by Apo C-II. Deficiency leads to Type I Hyperchylomicronemia.

Flashcard 25: Give the life cycle of HDL.

Answer: created by liver and intestine, delivers cholesterol from periphery to liver

Flashcard 26: What is the function of pancreatic lipase?

Answer: Degradation of dietary Triglycerides (TGs) in the small intestine

Extra: Pancreatic lipase breaks down dietary TGs into 2-monoacylglycerol and free fatty acids. It requires colipase for optimal activity in the presence of bile salts.

Flashcard 27: During starvation, what kind of fuels are used by muscles and liver? Why?

Answer: primarily FFA/ketones, reserving glucose for RBCs

Flashcard 28: What are ketones usually dervied from?

Answer: fatty acids, amino acids

Flashcard 29: How many kcal are produced per gram of fat?

Answer: 9 kcal

Flashcard 30: Why are ketones usually produced?

Answer: oxidation fuel source during starvation