Gut hormones in relation to body mass and torpor pattern changes during food restriction and re-feeding in the gray mouse lemur.

Potential implications of gut hormones in body mass and torpor and behavioral pattern changes induced by an incremental (40 and 80%) calorie restriction (CR) in long-days (LD, summer) and short-days (SD, winter) were investigated in gray mouse lemurs. Only 80% food-deprived LD and SD animals showed a continuous mass loss resulting in a 10 and 15% mass reduction, respectively. Ghrelin levels of all food-deprived groups increased by 2.6-fold on average and remained high after re-feeding while peptide YY (PYY) levels increased by 3.8-fold only in LD animals under 80% CR. In the re-fed SD group, body mass was positively associated with ghrelin and negatively associated with PYY, while no correlations were noted in the re-fed LD animals. Plasma glucagon-like peptide-1 (GLP-1) increased by 2.9-fold only in LD food-restricted mouse lemurs and was negatively associated with the minimal body temperature. No significant correlations were reported in food-deprived SD animals. These results suggest that ghrelin, PYY and GLP-1 may be related to pre-wintering fattening mechanisms and to the modulation of torpor expression, respectively. Such observation clearly warrants further investigations, but it opens an interesting area of research in torpor regulation.