Because muscles do not catabolize fatty acids during starvation. The oxaloacetate required to catabolize acetyl CoA from fatty acids is used to make glucose in the liver but not in muscles. There is sufficient glycolysis in muscle cells during starvation to provide the oxaloacetate needed to catabolize acetyl CoA in the Kreb s cycle. Lipoprotein lipase in muscles has a lower affinity for lipoproteins than the enzyme in fat tissue. Lipoprotein lipase is stimulated by glucagon through a second messenger mechanism.
Pancreatic lipase removes fatty acids from blood lipoproteins.
Chylomicrons are formed in the liver from lipids absorbed from the diet. The absorption of triglycerides that contain only medium chain fatty acids does not require bile salts.