Alcohol and its Biochemistry: Ethanol Metabolism
Alcohol is regarded as very light, attenuated oil, containing more of water than was present in ordinary oils. (Stahl, 2000). Alcohol is a general term denoting a family of organic chemicals with common properties. Members of this family include ethanol, methanol, butanol, propanol e.t.c (Google, 2010).
Alcohol is a clear volatile liquid that burns (oxidizes) easily. It has a slight characteristic odour and is very soluble in water.
It is an organic compound composed of carbon, hydrogen and oxygen, its chemical formula is C2H5OH
Heavy ethanol consumption may affect both blood cells and their bone marrow progenitors, although the mechanisms underlying such effects have remained obscure.Alcohol abuse is known to have a wide array of adverse effects on blood cells (Rosman and Lieber, 1994).
Alcohol has widespread direct and indirect effect on the hematologic system, which can mimic and or obscure other disorders.
Direct effects are primarily seen in the bone marrow and it involve the white cell, red cell and platelet lines such as the leucocytes, erythrocyte and thrombocyte production and functions are affected directly.
Indirect effects are secondary to metabolic or physiological alterations resulting in liver disease and to nutritional abnormalities caused by the effects of alcohol on absorption, storage and utilization of several vitamins (Heerman, 1998).
Although a small amount of ingested ethanol is excreted unchanged in the breadth and urine.
Over 95% is oxidatively metabolized to acetaldehyde and ultimately to acetate. Alcohol is metabolized mainly in the liver in two stages and catalyzed by alcohol and aldehyde dehydrogenases, with NAD+ as a hydrogen acceptor.
As can be seen from the pathway shown in figure I, the presence of alcohol within the cell makes a heavy demand on a limited supply of NAD+/NADH ratio. Other reactions that depend on NAD+ will thus be curtailed.
In particular, the oxidation of lactate to pyruvate will become much slower than the reverse reaction which accounts for the observed accumulation of lactate.
The second enzyme that converts acetaldehyde to acetate i.e aldehyde dehydrogenase is present not only in the liver but also in the peripheral tissues. Metabolism of alcohol in the liver. Apart from alcohol dehydrogenase which oxidize 95% of the alcohol in the body, a chain of enzymes known as microsomal ethanol oxidizing system (MEOS) oxidizes not only alcohol but also several classes of drugs.