The Energy Budget of Captive Siberian Hamsters, Phodopus sungorus, Exposed to Photoperiod Changes: Mass Loss Is Caused by a Voluntary Decrease in Food Intake

2000 ◽  
Vol 73 (4) ◽  
pp. 517-522 ◽  
Author(s):  
Loren D. Knopper ◽  
Patrice Boily
Keyword(s):  
Food Intake ◽  
Mass Loss ◽  
Energy Budget ◽  
Phodopus Sungorus ◽  
Siberian Hamsters

Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus)

2001 ◽  
Vol 281 (2) ◽  
pp. R519-R527 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Alessandra Cabrera ◽  
Irving Zucker
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Ventral Surface ◽  
Phodopus Sungorus ◽  
Ambient Temperatures ◽  
Siberian Hamsters ◽  
Daily Food ◽  
Brown Adipose ◽  
Wide Range ◽  
The Impact

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters ( Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2–3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5°C) than moderate (23°C) ambient temperatures. Removal of 8 cm2 of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm2 had no effect. An 8-cm2 fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.

Food hoarding is increased by pregnancy, lactation, and food deprivation in Siberian hamsters

1997 ◽  
Vol 272 (1) ◽  
pp. R118-R125 ◽  
Author(s):  
T. J. Bartness
Keyword(s):  
Food Intake ◽  
Body Mass ◽  
Food Deprivation ◽  
Phodopus Sungorus ◽  
Burrow System ◽  
Food Hoarding ◽  
Siberian Hamsters ◽  
Pregnancy And Lactation

Food hoarding by male Siberian hamsters (Phodopus sungorus sungorus) is increased only when body mass (fat) is decreased. Pregnancy and lactation result in marked decreases in lipid reserves (approximately 50%) in female Siberian hamsters. Therefore, the present experiments addressed the following questions: 1) Is food hoarding increased after food deprivation in female Siberian hamsters? and 2) How do food hoarding and food intake change during pregnancy, lactation, and their combination? During measurements in a simulated burrow system food hoarding increased after a 32-h fast (approximately 2- to 3-fold) to a level similar to that seen previously in males and was markedly increased during pregnancy (approximately 12- to 18-fold, lactation, and concurrent pregnancy and lactation (approximately 10- to 25-fold for each of the latter 2 conditions). Postfast food intake was not different from prefast baseline measures. Food intake was increased only during the last few days of pregnancy and was elevated throughout lactation. These impressive increases in the level of food hoarding during pregnancy, lactation and their combination suggest that food hoarding may play an important role in supplying easily accessible energy to subserve these reproductive conditions.

Control of torpor and body weight patterns by a seasonal timer in Siberian hamsters

1989 ◽  
Vol 257 (1) ◽  
pp. R142-R149 ◽  
Author(s):  
T. J. Bartness ◽  
J. A. Elliott ◽  
B. D. Goldman
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Implant Removal ◽  
Daily Torpor ◽  
Short Day ◽  
Siberian Hamsters ◽  
Long Day ◽  
Preparatory Phase ◽  
Pelage Color ◽  
Seasonal Responses

Two experiments were designed to assess whether the short-day-induced patterns of shallow daily torpor, body weight, and other seasonal responses (food intake and pelage pigmentation) exhibited by Siberian hamsters (Phodopus sungorus sungorus) are under the control of a "seasonal timekeeping mechanism" that is independent of reproductive status [testosterone, (T)]. We examined whether the patterning and expression of these seasonal responses were altered by decreases in serum T that accompany gonadal regression during the first 8 wk of short-day exposure (i.e., the "preparatory phase" of the torpor season) or by experimental increases in serum T after this phase. Short-day-housed, castrated hamsters bearing T implants had long-day levels of the hormone and did not exhibit torpor. Appropriate seasonal patterns and levels of torpor, body weight, pelage color stage, and food intake were exhibited after T implant removal although serum T was clamped to long-day levels during the preparatory phase. In animals that were gonad intact during the preparatory phase and were subsequently castrated and given T implants, torpor did not occur as long as the implants were in place. However, the patterns and levels of daily torpor, food intake, and body weight rapidly returned to appropriate seasonal values compared with the castrated, blank-implanted controls on T implant removal; these effects occurred whether the T implants were removed when torpor frequency was increasing, at its peak, or decreasing across the torpor season. T did not affect pelage color stage under any condition.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Peripubertal Immune Challenges Attenuate Reproductive Development in Male Siberian Hamsters (Phodopus sungorus)1

2004 ◽  
Vol 70 (3) ◽  
pp. 813-820 ◽  
Author(s):  
Brian J. Prendergast ◽  
Andrew K. Hotchkiss ◽  
Staci D. Bilbo ◽  
Randy J. Nelson
Keyword(s):  
Reproductive Development ◽  
Phodopus Sungorus ◽  
Siberian Hamsters ◽  
Immune Challenges

scholarly journals Photoperiod and Testosterone Interact to Drive Seasonal Changes in Kisspeptin Expression in Siberian Hamsters (Phodopus sungorus )

2008 ◽  
Vol 20 (12) ◽  
pp. 1339-1347 ◽  
Author(s):  
T. J. Greives ◽  
S. A. Humber ◽  
A. N. Goldstein ◽  
M.-A. L. Scotti ◽  
G. E. Demas ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Phodopus Sungorus ◽  
Siberian Hamsters

NPY Y1 receptor antagonist prevents NPY-induced torporlike hypothermia in cold-acclimated Siberian hamsters

2008 ◽  
Vol 294 (1) ◽  
pp. R236-R245 ◽  
Author(s):  
John Dark ◽  
Kimberly M. Pelz
Keyword(s):  
Body Temperature ◽  
Receptor Antagonist ◽  
Receptor Agonist ◽  
Phodopus Sungorus ◽  
Food Ingestion ◽  
Research Groups ◽  
Ambient Temperatures ◽  
Y1 Receptor ◽  
Siberian Hamsters ◽  
Intracerebroventricular Injections

Siberian hamsters ( Phodopus sungorus) undergo bouts of daily torpor during which body temperature decreases by as much as 20°C and provides a significant savings in energy expenditure. Natural torpor in this species is normally triggered by winterlike photoperiods and low ambient temperatures. Intracerebroventricular injection of neuropeptide Y (NPY) reliably induces torporlike hypothermia that resembles natural torpor. NPY-induced torporlike hypothermia is also produced by intracerebroventricular injections of an NPY Y1 receptor agonist but not by injections of an NPY Y5 receptor agonist. In this research, groups of cold-acclimated Siberian hamsters were either coinjected with a Y1 receptor antagonist (1229U91) and NPY or were coinjected with a Y5 receptor antagonist ( CGP71683 ) and NPY in counterbalanced designs. Paired vehicle + NPY induced torporlike hypothermia in 92% of the hamsters, whereas coinjection of Y1 antagonist + NPY induced torporlike hypothermia in 4% of the hamsters. In contrast, paired injections of vehicle + NPY and Y5 antagonist + NPY induced torporlike hypothermia in 100% and 91% of the hamsters, respectively. Although Y5 antagonist treatment alone had no effect on body temperature, Y1 antagonist injections produced hyperthermia compared with controls. Both Y1 antagonist and Y5 antagonist injections significantly reduced food ingestion 24 h after treatment. We conclude that activation of NPY 1 receptors is both sufficient and necessary for NPY-induced torporlike hypothermia.

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