Other meanings of Hepatocyte
Cell Biology
The hepatocyte is the predominant functional cell type of the liver, constituting roughly 80% of the organ's mass and performing a vast array of metabolic, synthetic, and detoxifying roles essential for homeostasis.
Hepatocytes are polygonal epithelial cells with abundant mitochondria, rough and smooth endoplasmic reticulum, and numerous peroxisomes, reflecting their high metabolic activity. They are arranged in one-cell-thick plates (cords) that radiate from the central vein of each liver lobule, with adjacent plates separated by sinusoids—fenestrated capillaries lined by endothelial cells and Kupffer cells. The apical surfaces of hepatocytes form bile canaliculi, tiny channels that collect bile and drain into the biliary tree. This polarized architecture allows hepatocytes to exchange substances with blood on their sinusoidal side and secrete bile on their canalicular side.
Hepatocytes are the workhorses of the liver, performing hundreds of essential tasks. They synthesize most plasma proteins, including albumin, clotting factors, and complement components, and they regulate glucose homeostasis through glycogenesis, glycogenolysis, and gluconeogenesis. They also metabolize lipids, cholesterol, and lipoproteins, and they are the primary site of urea synthesis, converting ammonia to urea for excretion. In addition, hepatocytes detoxify drugs and xenobiotics via phase I (cytochrome P450) and phase II (conjugation) reactions, and they store glycogen, iron, and fat-soluble vitamins. Their role in bile production—secreting bile salts, bilirubin, and phospholipids—is critical for fat digestion and waste elimination.
Hepatocytes have a remarkable capacity to regenerate; after partial hepatectomy, the remaining cells proliferate to restore liver mass within days, a process orchestrated by cytokines such as IL-6 and growth factors like HGF. This regenerative ability is exploited in living-donor liver transplantation. However, chronic injury—from viral hepatitis, alcohol, or metabolic disease—can lead to hepatocyte apoptosis, fibrosis, and cirrhosis. Hepatocyte dysfunction underlies many inherited metabolic disorders, such as Wilson disease and alpha-1 antitrypsin deficiency, and hepatocyte transplantation is being explored as a therapy for such conditions. Hepatocellular carcinoma, the most common primary liver cancer, arises from malignant transformation of hepatocytes, often in the setting of cirrhosis.
Beyond their textbook roles, hepatocytes exhibit several lesser-known features. They are among the few cells that can perform both glycolysis and gluconeogenesis simultaneously, with the direction of flux controlled by hormonal signals. Hepatocytes also express a unique set of transporters, such as OATP and MRP, that determine drug disposition and can be exploited for targeted drug delivery. In zebrafish, hepatocytes regenerate through a different mechanism than in mammals, involving biliary epithelial cells transdifferentiating into hepatocytes. Additionally, hepatocytes are highly polarized, and disruption of this polarity is an early event in cholestatic liver disease. They also play a role in innate immunity by secreting acute-phase proteins like C-reactive protein. Finally, hepatocytes have a remarkable ability to store fat, but excessive accumulation leads to non-alcoholic fatty liver disease, now the most common chronic liver condition worldwide.
Hepatocytes are central to liver function and are a key focus of hepatology research.
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