Golgi complex chylomicrons secreted from

VLDL is processed in the Golgi complex and secreted into the blood by the liver (Figs. 33.22 and 33.23). The fatty acid residues of the triacylglycerols ultimately are stored in the triacylglycerols of adipose cells. Note that, in comparison to chylomicrons (see Chapter 32), VLDL particles are more dense, as they contain a lower percentage of triglyceride than do the chylomicrons. Similar to chylomicrons, VLDL particles are first synthesized in a nascent form, and on entering the circulation they acquire apoproteins CII and E from HDL particles to become mature VLDL particles. 

Liver Storage and Release of Retinol Tissues can take up retinyl esters from chylomicrons, but most is left in the chylomicron remnants that are taken up into the liver by endocytosis. The retinyl esters are hydrolyzed at the hepatocyte cell membrane, and free retinol is transferred to the rough endoplasmic reticulum, where it binds to apo-RBP. Holo-RBP then migrates through the smooth endoplasmic reticulum to the Golgi and is secreted as a 1 1 complex with the thyroid hormone binding protein, transthyretin (Section 2.2.3). 

Fig. 32.10. Formation and secretion of chylomicrons. The triacylglycerol is produced in the smooth endoplasmic reticulum (SER) of intestinal epithelial cells from the digestive products, fatty acids, and 2-monoacylglycerols. The protein is synthesized in the rough endoplasmic reticulum (RER). The major apoprotein in chylomicrons is B-48. Assembly of the lipoproteins occurs in both the ER and the Golgi complex.

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