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

Abstract

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.

Coping with chaos: unpredictable food supplies intensify torpor use in an arid-zone marsupial, the fat-tailed dunnart (Sminthopsis crassicaudata)

“…But what is important in our study is that we have controlled food intakes in a manner that induced torpor responses to a pattern of unpredictability, rather than simply providing a different level of energy restriction. Our data are suggestive that torpor in fat-tailed dunnarts is largely a response to immediate food intakes, probably mediated by body condition, but involving food-factors and hormonal triggers associated with feeding (Ruf et al 1991;Westman and Gesier 2004;Giroud et al 2009). …”

“…The ecological benefits of torpor often have been inferred from laboratory studies that rely on food restriction to trigger a torpor response (e.g. Godfrey 1968;Geiser and Baudinette 1987;Geiser 1994;Lovegrove and Raman 1998;Song et al 1998;Giroud et al 2009). The intensity of such induced torpors (i.e.…”

Cholecystokinin activation of central satiety centers changes seasonally in a mammalian hibernator

“…Thus, the decline in the number of Fos-positive neurons over the active season may result from increased fattening and leptin resistance. Appetite regulation in mammals is a highly complex process, making it likely that other mechanisms contribute to satiation in hibernating species including action of the gut hormones ghrelin and peptide YY, insulin, neuropeptide Y, and hypothalamic AMP kinase [6,8,16,17,19,20,23]. …”

Resveratrol suppresses body mass gain in a seasonal non-human primate model of obesity

“…Because previous studies on mouse lemurs have suggested that several gut hormones may be related to the pre-wintering fattening phase and to the daily heterothermia expression [17], we also tested the effects of RSV supplementation on several gut-derived peptide hormones that are involved in numerous aspects of fuel homeostasis [18]. We measured glucagon-like peptide 1 (GLP-1), pancreatic polypeptide (PP), peptide YY (PYY) and glucose-dependent insulinotropic polypeptide (GIP).…”