Flashcards in ethanol metabolism Deck (31):
calories from ethanol
-4th major nutrient that provides energy
-empty calories because they have no nutritional value
-98 grams per drink for ethanol only!
lifestyle choice death
alcoholism is the IMMEDIATE cause of what?
What is the first organ effected by alcoholism?
why is ethanol easily absorbed by intestine and readily entered into the blood stream?
-water and fat soluble
-requires no digestion or enzymes to break it down
why do we have an enzyme that specifically works on alcohol?
-intestinal flora use fermentation so we developed the enzyme to handle ethanol
Majority of ethanol is matabolized...
in the liver by two different pathways
2. MEOS using cyt-P450 enzymes
-does not use energy
-ADH makes toxic acetaldehyde, ALDH turns that into acetate
-acetate goes into blood then goes to acetyl CoA in muscles for TCA cycle
what is the rate-limiting step in ADH system?
-ADH (alcohol dehydrogenase)
What is the limiting factor for alcohol metabolism?
Zero order kinetics
-a constant amount of drug is eliminated per unit of time
Km of ADH
-saturated after one drink
-if you continue to drink, it stays in the blood stream until the enzyme is done breaking down the first drink
generally, people metabolize...
10g of alcohol per hour
-blood alcohol level decreases 0.15g/L every hour
-single amino acid substitution (Glu to Lys)
What accumulates with atypical ALDH?
-cant turn it into acetate
-inhibits aldehyde dehydrogenase(ALDH)
-accumulation of acetaldehyde
-used in treatment for alcoholics
What happens if a person keeps drinking past the pain on disulfiram?
-damage caused by acetabldehyde that is seen in long time alcoholics will be ACCELERATED
processing of alcohol produces a large amount of...
NADH in the liver
Why is a build up of NADH so bad?
-can alter many metabolic processes
-significant effects are found in heavy drinkers of binge drinkers
build up of NADH in well fed state
-liver is taking up glucose and performing glycolysis, producing NADH and pyruvate
-adding more NADH to this amount will inhibit PDH complex and force it into pyruvate
-lactic acidosis and hyperuricemia
build up of NADH in fasting state
-liver will try to perform GNG, but NADH inhibits it so it is diverted to lactate
is alcohol a substrate for GNG?
-it is ketogenic, not glucogenic
-NADH inhibits oxidation of fatty acids
-accumulation of TAG as liquid droplets
-fatty liver disease which can lead to hyperlipidemia
Acetyl CoA and build up of NADH
-NADH inhibits TCA cycle
-OAA is converted back into malate to generate NAD+
-Acetyl CoA is forced into ketone synthesis and can result in ketoacidosis
free radical production
-induction of cyt-P450 produce more free radicals and therefore, more damaged cells
-acetaldehyde is a reactive compound that limits cells ability to neutralize free radicals
-results in cirrhosis and liver failure
what deficiency causes wernicke-korsakoff syndrome?
-damage is not permanent and can be reversed with supplements
-confusion, tremors, vision problems
-progression of wernicke
-memory loss, hallucinations
-irreversible and permanent brain damage
-fetal alcohol spectrum disorder
-disorders caused by prenatal alcohol exposure
-first three months are especially harmful