Final answer:
The liver can oxidize about one ounce of hard liquor per hour, with the enzymatic oxidation process being a zeroth-order reaction and rates of metabolism varying individually. The MEOS pathway becomes significant during heavy drinking, and overall alcohol metabolism is critical for preventing toxicity.
Step-by-step explanation:
The liver is capable of oxidizing approximately one ounce of hard liquor per hour. Oxidation of ethanol in the liver occurs primarily through two metabolic pathways, of which the most significant is catalyzed by the enzyme alcohol dehydrogenase. This reaction is considered a zeroth-order reaction. With the liver responsible for metabolizing between 85% to 98% of ethanol, an average 70 kg person typically takes about 2.5 hours to oxidize 15 mL of ethanol. However, individual rates can vary by 25-30% depending on factors like the amount of alcohol dehydrogenase present and body size.
During periods of heavy drinking, another pathway called the microsomal ethanol oxidizing system (MEOS) becomes more involved in ethanol metabolism. Normally accounting for 10 to 20% of liver ethanol uptake in moderate drinkers, MEOS activity increases with heavy alcohol intake. This is because the body upregulates MEOS enzymes to more rapidly clear excess ethanol.
Alcohol metabolism is an essential liver function and the only effective means to prevent alcohol toxicity. Considering that factors like gender and body mass index can affect metabolism rates, women metabolize alcohol slightly slower than men.