Lipoproteinproduktion

Lipoproteinproduktion refers to the cellular synthesis and secretion of lipoproteins, which are complexes of lipids and apolipoproteins that transport hydrophobic lipids such as triglycerides, cholesterol, and phospholipids through the aqueous environment of the bloodstream. The process is predominantly carried out by hepatocytes in the liver and by enterocytes lining the small intestine, although other tissues can contribute to specific lipoprotein subclasses. In hepatocytes, the synthesis of very low‑density lipoproteins (VLDL) begins in the endoplasmic reticulum, where apolipoprotein B100 is co‑translationally lipidated. Subsequent loading of triglycerides by microsomal triglyceride transfer protein creates nascent VLDL, which is then helically folded within the endoplasmic reticulum and trafficked through the Golgi apparatus before being secreted into the plasma.

Intestinal enterocytes produce chylomicrons that transport dietary triglycerides and cholesterol from the lumen into the lymphatic system. Apolipoprotein B48, a truncated form of apoB100, is synthesized in the enterocyte and initiates chylomicron assembly in a similar manner to VLDL formation. Once in the bloodstream, lipoproteins undergo remodeling by lipoprotein lipase, hepatic lipase, and cholesteryl ester transfer protein, which convert VLDL to LDL, LDL to IDL, and LDL to HDL particles.

The production and secretion of lipoproteins are tightly regulated by hormonal signals (insulin, glucagon), transcription factors (SREBP‑1c, PPARα), and nutritional status. Dysregulation can lead to hyperlipidemia and atherosclerosis, making the study of lipoproteinproduktion critical for understanding cardiovascular disease. Analytical methods for assessing lipoprotein production include isotope‑labeling experiments, quantitative lipidomics, and reverse phase HPLC separation coupled with mass spectrometry to determine lipoprotein subclass distribution and apolipoprotein composition.