Hepatic metabolism pathways

Hepatic metabolism pathways represent the collective biochemical reactions occurring within the liver that facilitate the processing of endogenous compounds and the detoxification of exogenous substances, such as drugs and environmental toxins (StatPearls: Physiology, Liver, 2023). These pathways are traditionally categorized into Phase I reactions, involving oxidation, reduction, and hydrolysis—largely mediated by Cytochrome P450 enzymes—and Phase II reactions, involving conjugation to increase water solubility for excretion (NIH: Drug Metabolism, 2022). Beyond xenobiotic clearance, these pathways are integral to maintaining systemic homeostasis through the regulation of carbohydrate, lipid, and amino acid metabolism (Wikipedia: Hepatic metabolism). Dysfunction in these pathways is a hallmark of various liver diseases and is the primary driver of drug-induced liver injury (DILI) and significant drug-drug interactions (PubMed: PMCID PMC4462723). Furthermore, the study of these pathways is essential for predicting the pharmacokinetic profile of new chemical entities during drug development (FDA: Drug Development and Drug Interactions). Because this term describes a broad set of physiological processes rather than a single protein or receptor, it is considered a pathway collection rather than a discrete therapeutic target.

Other names

Liver metabolismHepatic biotransformationXenobiotic metabolismHepatic drug metabolism

Modulation of enzymatic activity (induction or inhibition) and substrate conversion within Phase I and Phase II metabolic reactions (NIH: Drug Metabolism, 2022).