Inhibition of Daily Torpor in Mice Requires Calories, Not Just Feeding: A Potential Role for GLP-1

Torpor is an energy-saving physiological state characterized by a drop in the metabolic rate of the animal, followed by a decrease in core body temperature (Tb). In mice, daily torpor can be avoided through food consumption, but it remains unclear whether this effect is due to the physical presence of food in the digestive system or the caloric content of the meal. We hypothesized that physical digestion or distension is sufficient to prevent torpor, even in the absence of calories. To test this, C57Bl/6J female mice were implanted with temperature telemeters and calorically restricted until they consistently entered torpor, as defined by minimum Tb below 30°C. These mice were then given ad libitum access to either caloric gelatin (caloric density of 1.0 kcal/g) or a very low-calorie (VLC) gelatin diet (caloric density of 0.05 kcal/g). Mice that consumed the VLC diet continued to enter torpor (minimum Tb of 23.7 ± 0.6°C), whereas consumption of caloric gelatin prevented torpor with a significant increase in minimum Tb (34.4 ± 0.6°C, p < 0.05 vs. VLC). Further, daily torpor was blocked by consumption of any of the caloric macromolecules: carbohydrates, fats, or proteins. We next investigated whether this caloric effect was mediated by gut hormones. Circulating glucagon-like peptide 1 (GLP-1) was relatively low in mice given the VLC diet (when torpor occurred) (50.6 ± 16.1 pM) and significantly elevated during caloric feeding (when torpor was inhibited) (91.7 ± 17.4 pM, p < 0.05 vs. VLC). Administration of 1.0 mg/kg liraglutide, a GLP-1 receptor agonist, prevented calorically-restricted mice from entering torpor (minimum Tb of 33.6 ± 1.5°C). Together, these data suggest that the initial hypothesis was incorrect and that GLP-1 may mediate the suppression of daily torpor in the mouse in response to the input of calories from a meal. All results are reported as mean ± standard deviation. This study was funded internally by Williams College. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.