Digestive system ↗Portal blood enters sinusoids
Absorbed water-soluble nutrients and gut-derived molecules reach hepatocytes through a fenestrated exchange bed.
DIGESTIVE / LIVER METABOLISM
First-pass hub.
Not a vague “detox.”
The liver receives portal nutrients, buffers glucose, handles amino nitrogen, packages lipid, produces bile and transforms many endogenous molecules, medicines and toxicants. Transformation can inactivate, activate, or create reactive intermediates.
12-STAGE MAP
Processing has
multiple outputs.
“Detoxification” is not one pathway and does not imply that a product can cleanse the liver. Dose, route, enzymes, transport, genetics, interactions and liver health change handling.
Glucose is buffered
Glycogen synthesis, glycolysis and reduced glucose output coordinate the fed state; fasting reverses key fluxes.
Lipid is routed
Fatty-acid oxidation, triglyceride storage, de novo synthesis and VLDL export compete according to substrate and signals.
Nitrogen becomes urea
Hepatic pathways capture ammonia and amino nitrogen for urea-cycle disposal.
Phase I changes molecules
Oxidation, reduction or hydrolysis—often involving CYP enzymes—can expose functional groups or form active intermediates.
Phase II conjugates
Glucuronidation, sulfation, glutathione and other reactions often increase water compatibility.
Transporters move products
Metabolites may enter bile or blood for fecal or renal elimination; some compounds recirculate.
Injury is a separate branch
Reactive metabolites, immune responses, mitochondrial stress and dose can produce drug-induced liver injury in susceptible people.
ADH makes acetaldehyde
Alcohol dehydrogenase oxidizes ethanol, producing toxic acetaldehyde and NADH.
ALDH makes acetate
Aldehyde dehydrogenase oxidizes acetaldehyde and generates more NADH.
Redox redirects metabolism
A higher NADH/NAD+ ratio alters lactate/pyruvate balance, gluconeogenesis and lipid oxidation.
Repeated injury can progress
Steatosis, inflammation and fibrosis are distinct, non-inevitable stages influenced by dose pattern and susceptibility.