El metabolismo hepatico del etanol y su contribucion a la enfermedad hepatica por alcohol

In human, liver is the principal organ for the metabolism of ethanol because posses three systems for the oxidation of ethanol to acetaldehyde. These systems are alcohol dehydrogenase (ADH, in cytosol), catalase (in peroxisoma) and cytochrome P-450 (in smooth endoplasmic reticulum; this system is called MEOS). These systems convert ethanol to acethaldeyde with reduction of a molecule of NAD + or NADP + to NADH and NADPH, respectively. Acetaldehyde gets in to the mitochondria where it is oxidized to acetate for the enzyme aldehyde dehydrogenase (ALDH) with reduction of NAD + to NADH. ADH is the principal enzyme for the metabolism of ethanol during an acute ingestion of ethanol. Oxidation of ethanol by ADH represent 85% and by both catalase and MEOS system represents 15%, these two before mentioned systems are namely alternative metabolie pathways ethanol of oxidation. Also chronic alcoholism induces catalase and MEOS systems by which 40% of ethanol metabolism takes place. Ethanol oxidation to acetate in cytosol produces alterations at major metabolic pathways in both sub-cellular compartments. These alterations account for the damage to liver when alternative oxidation systems are induced.