Ever wondered why you feel the need to reach out to a glass of water soon after you have finished your pastry? It could be your brain's defence mechanism. Scientists have identified a hormone that acts on the brain to stimulate thirst in response to sugar and alcohol, thereby preventing dehydration.
The researchers identified that the liver hormone or fibroblast growth factor 21 (FGF21) acts via the brain's reward pathway in mice to suppress the desire for sugar and alcohol in favour of drinking water.
The scientists revealed that while they know that exposure to alcohol or sugar turns on production of FGF21 in the liver. Here they demonstrate how this hormone then travels in the blood to the hypothalamus, to stimulate thirst, which in turn helps prevent dehydration.
The researchers were surprised to see the new independent pathway of FGF21. This new pathway worked independently of the classical renin-angiotensin-aldosterone thirst pathway in the kidneys
The hormone regulated hydration (water drinking) was found in response to nutrient stress.The normal mice and mice genetically unable to produce FGF21 drank similar amounts of water when given the typical chow diet.
It was found that a high-fat/low-carbohydrate ketogenic diet stimulated water drinking in normal mice while mice genetically unable to produce FGF21 failed to increase water intake in response to that nutritional stress.
The researchers claimed that these findings confirmed the hormone's role in the signalling pathway.
The scientists also said that there was a very strong response to the hormone in humans. Scientists could explore the hormone pathway to investigate further.
For the study, 21 people were randomly assigned to drink either a mixture of alcohol and juice, or juice alone. The researchers measured their FGF21 blood levels after four hours. The findings revealed that in response to alcohol, FGF21 levels spiked at around two hours and fell after that.
Scientists are affirmative that FGF21 might someday be used as a drug to limit alcohol consumption and protect against its effects in people.
The study was published in the
journal Cell Metabolism.