Scientifically Speaking | Could drunk mice help people get sober quicker?
To understand how a hormone made in the liver called FGF21 helps the brain deal with the effects of alcohol, researchers at the University of Texas-Southwestern turned to mice. Here's what they found:
In the Bimal Roy film Devdas, Dilip Kumar lamented that he drank not to tolerate life but to be able to breathe, adding that since he could not get up when he was drunk, he was forced to stay where he was. Laboratory mice are similar to the inebriated Devdas Mukherjee in that they are immobilised when they’re drunk. A new study finds, however, that a shot of a hormone might help them get up quicker.
Here’s the full story. To understand how a hormone made in the liver called fibroblast growth factor 21, or FGF21, helps the brain deal with the effects of alcohol, researchers at the University of Texas-Southwestern turned to mice.
Why mice? Because these experiments could not be done on people. Mice get tipsy from alcohol. In addition, there are fewer ethical barriers to getting mice drunk or testing the effects of alcohol on genetically-modified animals created to lack functional FGF21. The researchers reported their findings in a new study published in the journal Cell Metabolism.
Sobering up after drinking excessive alcohol takes time. In earlier studies, FGF21 was shown to suppress alcohol preference and encourage drinking of water in intoxicated mice to prevent dehydration and other responsible behaviours.
In the current study, scientists found genetically-modified mice that didn’t make FGF21 needed more time to recover than standard mice after alcohol ingestion. Mice that have been incapacitated by alcohol typically took about three hours to regain consciousness. On the other hand, those that received an extra shot of FGF21 were able to recover from the effects of alcohol in around half the time — suggesting a direct role for the hormone in coordination after alcohol consumption.
A question you may have never thought to ask before reading this column is — how do you go about getting mice drunk and checking for the effects of alcohol intoxication? The research article offers details here as well. Mice were fed “a binge ethanol dose” by tube and were subjected to a rodent equivalent of a sobriety test which consisted of placing them down in V-shaped troughs and measuring their ability to right themselves. All for science!
How does FGF21 exert its rousing effects? Crucially, the shot of FGF21 didn’t actually reduce blood alcohol concentrations in mice. There are other enzymes that deal with alcohol metabolism, and I’ll get to that shortly. Instead, FGF21 made the mice better able to deal with alcohol intoxication. One of the lead authors, Steven Kliewer, notes that “FGF21 does this by activating a very specific part of the brain that controls alertness.”
Interestingly, the authors also found that the effects of FGF21 seem to be alcohol-specific: They were not able to arouse mice after they were made unconscious using three other drugs with sedative properties. So, it looks like mice (and possibly, humans) have a hormone that helps to deal with the ill effects of alcohol intoxication. FGF21 is also induced by other stressors such as starvation, so it has other roles as well.
The ultimate goal is, however, not to test alcohol intoxication and its detrimental impacts on mice but to see if the results extend to people. In this respect, this study is a starting point. This is a limitation of the study that the authors themselves acknowledge.
But how alcohol is consumed and dealt with by animals raises all sorts of other questions. People engage in social drinking in many cultures, but it isn’t immediately obvious why digestive enzymes would’ve evolved to break down alcohol in the first place in our animal ancestors.
It turns out that humans aren’t the first animals that have developed a taste for booze.
Rotting fruit can accumulate up to 4% alcohol through the process of fermentation. And alcohol is a great source of calories for animals (though is not always great news for diet-conscious human drinkers).
There are many animals (in addition to mice) that can get inebriated. But it may also surprise you to know that not all animals metabolise alcohol equally well.
Some animals get drunk more easily than others and a lot of it has to do with their exposure to fruits with the potential to ferment. For example, hamsters are incredibly difficult to get drunk. Scaled up to average-sized humans, these tiny rodents can drink the equivalent of 1.5 litres of pure alcohol. Their trick is possessing a lot of different variants of alcohol dehydrogenase — the liver enzymes that break alcohol down. Cows, elephants, and horses on the other hand do not deal well with even small amounts of booze!
Humans, who are somewhere between hamsters and elephants would do well to avoid alcohol or to drink in moderation.
Anirban Mahapatra is a scientist by training and the author of a book on COVID-19
The views expressed are personal