Socially stressed hamsters overeat
Golden hamsters suffering from social stress will eat more than necessary. This observation surprised scientists at Georgia State University, as they have not been able to observe the stress-induced weight gain known in humans in any model organism, such as rats or mice. On the contrary, socially stressed rats and mice refuse their food and lose weight.
The researchers placed an eleven-month-old hamster in the cage of a dominant, older hamster for seven minutes at a time. Typically, the older animal would start chasing and attacking the younger one within a minute.
Bartness and his team were able to show that the younger hamster was eating significantly more food after only four confrontations in the strange cage. Interestingly, the food intake also led to an increase in visceral fat, which, unlike subcutaneous fat, is located beneath the abdominal wall. The researchers observed a different build-up of fat when they confronted the hamster with the aggressive conspecific at irregular intervals instead of at a fixed time.
Eating binges triggered by social stress also lead to the build-up of visceral fat in humans, which is associated with diabetes and cancer. In further studies with the golden hamster, the behavioral researchers want to find out whether the primary stress hormone in hamsters and humans, cortisol, is responsible for the build-up of fat. Then it might be possible to develop a drug that stops the release of stress hormones or blocks the hormone-induced signaling cascade that leads to fat gain.
