What is S6K? Brain Enzyme Controls Appetite and Weight Loss

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According to a new study, published in the prestigious medical journal Cell Metabolism, a brain enzyme may be the key in controlling appetite and weight loss. Researchers from the College of Medicine of Yeshiva University were able to find a brain enzyme called p70 S6 Kinase 1 (or S6K) as the responsible for regulating people weight gain and obesity.

According to the study, researchers focused on enzymes produced in the hypothalamus, a gland located deep within the brain that is credited for controlling different body functions such as body temperature, thirst and hunger. The nerve cells present in the hypothalamus respond to stimulus exerted by certain nutrients such as carbs, proteins, and fats. Then, these hypothalamus cells send signals to increase or decrease food and liquid intake according to what they have sensed. The enzyme also adjust metabolic rates and physical activity accordingly. Researchers, led by Dr. Gary J. Schwartz, found that the enzyme, named p70 S6 Kinase 1, or S6K, and its biochemical pathway is nutrient-sensitive.

The Study’s Results

Researchers took an animal system (rats) and injected them with certain viruses that could raise or lower the S6K enzyme activity. What they found was that when the enzyme’s activity was increased, a reduction in food intake was observed. Also, a reduction in body weight was obtained and a reduction in small peptides (small amino acids chains) involved in feeding stimulation. On the contrary, when the enzyme activity was lowered there was an increase in feeding, in small peptide production, and an increase in body weight.

Researchers also found that rats on a high-fat diets which were given the S6K-enhancing virus, overate less and gained weight slower than control animals. In addition, the animals had lower body-fat contents and better glucose tolerance than the control group.

The Study´s Implication for Humans

Although the study was made on an animal system it demonstrated that the brain enzyme S6 Kinase 1, or S6K, act as food-sensing thermostat. By regulating the activity of this enzyme the feeding behavior and metabolism of a mammalian could be regulated to maintain a normal energy balance, thus to keep body weight in check. Also, drugs could be researched that enhance or depress the S6 kinase activity to increase/decrease body weight as needed.


Clémence Blouet, Hiraku Ono and Gary J. Schwartz. 2008. Mediobasal Hypothalamic p70 S6 Kinase 1 Modulates the Control of Energy Homeostasis. Cell Metabolism, Volume 8, Issue 6, 459-467


This post is part of the series: New research on Weight Loss

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