What is the mechanism behind "acquired" alcohol tolerance?

Question

I can understand natural variation in alcohol dehydrogenase (ADH) in a population leading to variation in rate of inebriation (after controlling for other variables -- e.g., mass, food consumption, etc.).But what physiological (adaptive?) process leads to increased alcohol tolerance over the long term in a single individual?

Answer 1

Most proteins can be made in varying amounts by your body. There's no point in making a ton of a protein that never gets used. On the other hand, it's also not helpful if a protein is super important, but only gets made in very small amounts.

ADH is able to be regulated this way. Your liver makes a base amount of ADH, but if someone drinks a lot over a long period of time, the body will compensate and make more ADH to break down the increased amount of alcohol. On the other hand, if the person quits for several months, the body will gradually slow down its production of ADH. That's why people say that their alcohol tolerance has decreased after a period of not drinking.

Answer 2

One current theory involves the sensitivity of the central GABA receptor system. You can google "gaba receptor and ethanol tolerance" and see what's being done in that field.