Reduced food intake during exposure to high ambient temperatures is associated with molecular changes in the nucleus of the hippocampal commissure and the paraventricular and arcuate hypothalamic nuclei

Goldthioglucose-obese mice cannot adjust their food intake to meet the increased energy requirements due to cold. At all ambient temperatures above 15°C the spontaneous running activity of these animals is less than that observed for nonobese controls. Activity of obese mice is maximal at 19°C and minimal at 15°C or lower. Body weights decrease during exposure to cold. In contrast to that of obese mice, running activity of nonobese controls is maximal at an ambient temperature of 25°C but nearly ceases at 15°C or lower. The food intake of these animals increases in the cold and remains elevated even at temperatures at which activity decreases. The body weight of nonobese controls is either maintained constant or increases during exposure to cold air.

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

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.281.2.r519 ◽

2001 ◽

Vol 281 (2) ◽

pp. R519-R527 ◽

Cited By ~ 9

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.

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Region-Specific Reduction in Leptin-Induced Phosphorylation of Signal Transducer and Activator of Transcription-3 (STAT3) in the Rat Hypothalamus Is Associated with Leptin Resistance during Pregnancy

Endocrinology ◽

10.1210/en.2004-0338 ◽

2004 ◽

Vol 145 (8) ◽

pp. 3704-3711 ◽

Cited By ~ 98

Author(s):

S. R. Ladyman ◽

D. R. Grattan

Keyword(s):

Food Intake ◽

Arcuate Nucleus ◽

Ventromedial Hypothalamus ◽

Leptin Resistance ◽

Signal Transducer ◽

Pregnant Rats ◽

Hypothalamic Nuclei ◽

Stat3 Phosphorylation ◽

Vehicle Treatment ◽

Plasma Leptin

Abstract Leptin concentrations increase during pregnancy, but this does not prevent the pregnancy-induced increase in food intake, suggesting a state of leptin resistance. This study investigated the response to intracerebroventricular leptin administration in pregnant rats. After fasting, nonpregnant, d-7 and d-14 pregnant rats received leptin (4 μg) or vehicle, then food intake was measured. Serial blood samples were collected in another group of rats to determine plasma leptin concentrations. Further groups of d-14 pregnant and nonpregnant rats were killed after leptin or vehicle treatment, and brains were collected. Hypothalamic nuclei were microdissected, and levels of signal transducer and activator of transcription (STAT)3 phosphorylation were measured using Western blot analysis. Fasting decreased leptin concentrations in both pregnant and nonpregnant rats. Leptin treatment significantly reduced food intake in nonpregnant and d-7 pregnant rats but not in d-14 pregnant rats. In addition, there was no postfasting hyperphagic response in the pregnant rats. In the pregnant rats, leptin-induced STAT3 phosphorylation was suppressed in the arcuate nucleus and, to a lesser extent, in the ventromedial hypothalamus (VMH), compared with nonpregnant rats. Unstimulated STAT3 levels were also decreased in the VMH during pregnancy. Leptin-induced phosphorylation of STAT3 in the dorsomedial and lateral hypothalamus was not different between pregnant and nonpregnant rats. These data indicate that pregnant rats become resistant to the satiety action of leptin. Furthermore, leptin-induced activation of the STAT3 is impaired during pregnancy, specifically in the arcuate nucleus and VMH. These data support the hypothesis that pregnancy is a state of hypothalamic leptin resistance.

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Gqα/G11α deficiency in dorsomedial hypothalamus leads to obesity resulting from decreased energy expenditure and impaired sympathetic nerve activity

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00059.2020 ◽

2020 ◽

Author(s):

Eric A. Wilson ◽

Hui Sun ◽

Zhenzhong Cui ◽

Marshal T. Jahnke ◽

Mritunjay Pandey ◽

...

Keyword(s):

Gene Expression ◽

Adipose Tissue ◽

Food Intake ◽

Energy Expenditure ◽

Energy Homeostasis ◽

Dorsomedial Hypothalamus ◽

Ambient Temperatures ◽

Brown Adipose ◽

Inhibit Food Intake ◽

Specific Deletion

The G protein subunits Gqα and G11α (Gq/11α) couple receptors to phospholipase C, leading to increased intracellular calcium. In this study we investigated the consequences of Gq/11α deficiency in the dorsomedial hypothalamus (DMH), a critical site for the control of energy homeostasis. Mice with DMH-specific deletion of Gq/11α (DMHGq/11KO) were generated by stereotaxic injection of AAV-Cre-GFP into the DMH of Gqαflox/flox:G11α-/- mice. Compared to control mice that received DMH injection of AAV-GFP, DMHGq/11KO mice developed obesity associated with reduced energy expenditure without significant changes in food intake or physical activity. DMHGq/11KO mice showed no defects in the ability of the melanocortin agonist melanotan II to acutely stimulate energy expenditure or to inhibit food intake. At room temperature (22oC) DMHGq/11KO mice showed reduced sympathetic nervous system activity in brown adipose tissue (BAT) and heart, accompanied with decreased basal BAT Ucp1 gene expression and lower heart rates. These mice were cold intolerant when acutely exposed to cold (6oC for 5 hours) and had decreased cold-stimulated BAT Ucp1 gene expression. DMHGq/11KO mice also failed to adapt to gradually declining ambient temperatures and to develop adipocyte browning in inguinal white adipose tissue although their BAT Ucp1 was proportionally stimulated. Consistent with impaired cold-induced thermogenesis, the onset of obesity in DMHGq/11KO mice was significantly delayed when housed under thermoneutral conditions (30ºC). Thus, our results show that Gqα and G11α in the DMH are required for the control of energy homeostasis by stimulating energy expenditure and thermoregulation.

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Analysis of energy expenditure at different ambient temperatures in mice lacking DGAT1

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00248.2002 ◽

2003 ◽

Vol 284 (1) ◽

pp. E213-E218 ◽

Cited By ~ 50

Author(s):

Hubert C. Chen ◽

Zuleika Ladha ◽

Steven J. Smith ◽

Robert V. Farese

Keyword(s):

Food Intake ◽

Energy Expenditure ◽

Ambient Temperature ◽

Cold Environment ◽

Normal Surface ◽

Ambient Temperatures ◽

Active Mechanism ◽

Key Enzyme ◽

Secondary Mechanism ◽

Obesity Resistance

Mice lacking acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1), a key enzyme in triglyceride synthesis, have increased energy expenditure and therefore are resistant to obesity. Because ambient temperature can significantly affect energy expenditure in mice, we undertook these studies to determine the effects of different ambient temperatures on energy expenditure, food intake, and thermoregulation in DGAT1-deficient [ Dgat1(−/−)] mice. Dgat1(−/−) mice had increased energy expenditure irrespective of changes in the ambient temperature. Although core temperature was normal, surface temperature was increased in Dgat1(−/−) mice, most likely reflecting an active mechanism to dissipate heat from increased thermogenesis. Dgat1(−/−) mice had increased food intake at baseline, and this hyperphagia became more pronounced upon exposure to cold. When fasted in a cold environment, Dgat1(−/−) mice developed hypothermia, which was associated with hypoglycemia. These results suggest that the hyperphagia in Dgat1(−/−) mice is a secondary mechanism that compensates for the increased utilization of fuel substrates. Our findings offer insights into the mechanisms of hyperphagia and increased energy expenditure in a murine model of obesity resistance.

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Hypothalamic mapping of orexigenic action and Fos-like immunoreactivity following relaxin-3 administration in male Wistar rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00346.2006 ◽

2007 ◽

Vol 292 (3) ◽

pp. E913-E919 ◽

Cited By ~ 41

Author(s):

B. M. McGowan ◽

S. A. Stanley ◽

N. E. White ◽

A. Spangeus ◽

M. Patterson ◽

...

Keyword(s):

Food Intake ◽

Supraoptic Nucleus ◽

Arcuate Nucleus ◽

Preoptic Area ◽

Disulphide Bonds ◽

Hypothalamic Nuclei ◽

Relaxin Family ◽

Male Wistar Rats ◽

Additional Support ◽

G Protein Coupled

The insulin superfamily, characterized by common disulphide bonds, includes not only insulin but also insulin-like peptides such as relaxin-1 and relaxin-3. The actions of relaxin-3 are largely unknown, but recent work suggests a role in regulation of food intake. Relaxin-3 mRNA is highly expressed in the nucleus incertus, which has extensive projections to the hypothalamus, and relaxin immunoreactivity is present in several hypothalamic nuclei. In the rat, relaxin-3 binds and activates both relaxin family peptide receptor 1, which also binds relaxin-1, and a previously orphaned G protein-coupled receptor, RXFP3. These receptors are extensively expressed in the hypothalamus. The aims of these studies were twofold: 1) map the hypothalamic site(s) of the orexigenic action of relaxin-3 and 2) examine the site(s) of neuronal activation following central relaxin-3 administration. After microinjection into hypothalamic sites, human relaxin-3 (H3; 180 pmol) significantly stimulated 0- to 1-h food intake in the supraoptic nucleus (SON), arcuate nucleus (ARC), and the anterior preoptic area (APOA) [SON 0.4 ± 0.2 (vehicle) vs. 2.9 ± 0.5 g (H3), P < 0.001; ARC 0.7 ± 0.3 (vehicle) vs. 2.7 ± 0.2 g (H3), P < 0.05; and APOA 0.8 ± 0.1 (vehicle) vs. 2.2 ± 0.2 g (H3), P < 0.05]. Cumulative food intake was significantly increased ≤8 h following administration into the SON and 4 h into the APOA. A significant increase in Fos-like immunoreactivity was seen in the SON following central relaxin-3 administration. Relaxin-3 stimulates feeding in several hypothalamic nuclei, and these studies provide additional support for relaxin-3 as an important peptide in appetite regulation.

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Photoperiodic entrainment of seasonal changes in appetite and growth in pony colts

Proceedings of the British Society of Animal Science ◽

10.1017/s0308229600033468 ◽

1998 ◽

Vol 1998 ◽

pp. 133-133

Author(s):

Z. Fuller ◽

J.E. Cox ◽

C. McG. Argo

Keyword(s):

Food Intake ◽

Seasonal Changes ◽

Environmental Pressures ◽

Ambient Temperatures ◽

Forage Availability ◽

Photoperiodic Regime ◽

Gross Energy ◽

Ad Libitum ◽

Pelleted Diet ◽

Voluntary Food Intake

During winter, voluntary food intake (VFI) and growth decreased in light horse weanlings given ad libitum access to a forage/concentrate diet (Cymbaluk et al, 1989). These changes were attributed to decreased ambient temperatures. However, photoperiodically entrained seasonal changes in VFI and growth are documented in other Northern ungulates (Moen, 1978) and may comprise an adaptation to changes in forage availability. Throughout their evolution, horses experienced similar environmental pressures and may demonstrate similar photoperiodic adaptations. This study characterised changes in VFI and growth in pony colts maintained under an artificial photoperiodic regime.Seven, 2 year-old pony colts of Welsh Mountain type (182.4 ± 5.4 kg), were obtained from pasture (53°N). Animals were individually housed in loose-boxes, within a light-proof building. Measured quantities of a complete pelleted diet (gross energy = 16.7 MJ.kgDM-1), calculated to exceed appetite by at least 1 kg, were offered daily.

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Effect of diurnally fluctuating high ambient temperatures on performance and feeding behaviour of multiparous lactating sows

Animal Science ◽

10.1017/s135772980005534x ◽

2000 ◽

Vol 71 (3) ◽

pp. 571-575 ◽

Cited By ~ 11

Author(s):

N. Quiniou ◽

D. Renaudeau ◽

S. Dubois ◽

J. Noblet

Keyword(s):

Food Intake ◽

Milk Production ◽

Feeding Behaviour ◽

Post Partum ◽

Lactation Performance ◽

Large White ◽

Ambient Temperatures ◽

Total Food Intake ◽

Daily Food ◽

Ad Libitum

AbstractForty-two multiparous Large White sows were used to investigate the effect of diurnally fluctuating temperature (T) on lactation performance and feeding behaviour. The animals were allocated to one of the four thermic treatments: constant T at 25°C (25C) and 29°C (29C) or equal-mean diurnal cyclic T varying from 21 to 29°C (25V) and from 25 to 33°C (29V). Photoperiod was fixed to 14 h of light. The sows were given food ad libitum between the 7th and the 19th day post partům. Lactation performance was measured for all sows whereas the feeding behaviour was recorded only on 28 sows. The ad libitum food intake was comparable at 25C and 25V (6•31 kg/day) as were milk production and body reserves mobilization. In contrast, food intake at 29V was higher than at 29C (4•53 v. 3•48 kg/day) with no difference in milk production between the two treatments. The increased daily food intake at 29V resulted from higher intakes over the coolest periods of the day and especially during the dark period. Neither meal size nor daily number of meals were significantly affected by T. Feeding behaviour was mainly diurnal but with differences between treatments: 0•90 of total food intake at 29C v. 0•78 at the other three T It appears that the effects of diurnally fluctuating T on lactation performance of sows depend on the mean level of T

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Increased heat loss affects hibernation in golden-mantled ground squirrels

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00670.2003 ◽

2004 ◽

Vol 287 (1) ◽

pp. R167-R173 ◽

Cited By ~ 10

Author(s):

Alexander S. Kauffman ◽

Matthew J. Paul ◽

Irving Zucker

Keyword(s):

Food Intake ◽

Heat Loss ◽

Body Mass ◽

Complete Removal ◽

Ground Squirrels ◽

Control Procedure ◽

Ambient Temperatures ◽

Spermophilus Lateralis ◽

Maintain Body Temperature ◽

Body Heat

During hibernation at ambient temperatures (Ta) above 0°C, rodents typically maintain body temperature (Tb) ∼1°C above Ta, reduce metabolic rate, and suspend or substantially reduce many physiological functions. We tested the extent to which the presence of an insulative pelage affects hibernation. Tb was recorded telemetrically in golden-mantled ground squirrels ( Spermophilus lateralis) housed at a Ta of 5°C; food intake and body mass were measured at regular intervals throughout the hibernation season and after the terminal arousal. Animals were subjected to complete removal of the dorsal fur or a control procedure after they had been in hibernation for 3–4 wk. Shaved squirrels continued to hibernate with little or no change in minimum Tb, bout duration, duration of periodic normothermic bouts, and food intake during normothermia. Rates of rewarming from torpor were, however, significantly slower in shaved squirrels, and rates of body mass loss were significantly higher, indicating increased depletion of white adipose energy stores. An insulative pelage evidently conserves energy over the course of the hibernation season by decreasing body heat loss and reducing energy expenditure during periodic arousals from torpor and subsequent intervals of normothermia. This prolongs the hibernation season by several weeks, thereby eliminating the debilitating consequences associated with premature emergence from hibernation.

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