What are liver microsomes?

Liver microsomes are tiny membrane-bound vesicles that are created in the laboratory from liver cells (hepatocytes). They are formed when liver tissue is gently broken down and the endoplasmic reticulum (ER)—the part of the cell responsible for protein and lipid synthesis—breaks into small fragments. During high-speed centrifugation, these fragments naturally reseal into microscopic vesicles called microsomes. Although they do not exist as separate structures inside living cells, they closely represent the enzyme-rich environment of the liver.

The main reason liver microsomes are so valuable is that they contain many of the liver’s drug-metabolising enzymes, especially the cytochrome P450 (CYP450) family. They also include other important enzymes, such as UDP-glucuronosyltransferases (UGTs) and flavin-containing monooxygenases (FMOs), which help break down drugs, toxins, and naturally occurring compounds in the body.

Liver microsomes are widely used in pharmaceutical, biomedical, and regenerative research to unveil how a new drug behaves before it reaches clinical trials. Scientists use them to measure how quickly a drug is metabolised, identify the metabolites it produces, evaluate potential drug-drug interactions, and assess whether a compound could cause liver toxicity. Because these studies can be performed in a controlled laboratory setting, they provide valuable insights while reducing the need for early animal or human testing.

In in-vitro research liver microsomes are a crucial tool for studying liver metabolism. Their ability to mimic many of the liver’s metabolic functions makes them essential for drug discovery, toxicology studies, pharmacokinetic research, and the development of safer and more effective medicines.