scholarly journals Signalling in body-weight homeostasis: neuroendocrine efferent signals

2000 ◽  
Vol 59 (3) ◽  
pp. 397-404 ◽  
Author(s):  
Jonathan Webber ◽  
Ian A. Macdonald
Keyword(s):  
Nervous System ◽  
Body Weight ◽  
Adipose Tissue ◽  
Weight Gain ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Resting Energy Expenditure ◽  
Excess Energy ◽  
Brown Adipose ◽  
Diet Induced Thermogenesis

Whilst a number of neuroendocrine afferent signals are implicated in body-weight homeostasis, the major efferent pathway is the sympathetic nervous system (SNS), which affects both energy expenditure and substrate utilization. Thyroid hormones and their interactions with the SNS may also have a role to play. Some of the variability in resting energy expenditure can be explained by differences in SNS activity, and β-blockade can reduce energy expenditure and diet-induced thermogenesis in Caucasians. Excess energy intake leads to SNS activation and increased diet-induced thermogenesis. A relationship has also been demonstrated between spontaneous physical activity and SNS activity. In many animal models the SNS activates brown adipose tissue thermogenesis, hence increasing diet-induced thermogenesis and dissipating excess energy as heat. This effect is mediated via β3-adrenoceptors and activation of an uncoupling protein unique to brown adipose tissue. Homologous proteins have been identified in human tissues and may play a role in human energy expenditure. How the SNS is implicated in this process is unclear at present. β3-Adrenoceptor polymorphism has been associated both with lower resting energy expenditure in some populations and with reduced autonomic nervous system activity. SNS effects on substrate cycling may also play a role. In the development of obesity the effects of the SNS in promoting lipolysis and fat oxidation are likely to be at least as important as its effects on thermogenesis. β-Blockade has relatively small effects on energy expenditure, but more pronounced effects on reducing lipid oxidation, so tending to favour fat storage and weight gain. Low lipid oxidation is a risk factor for weight gain, and there is some evidence that low basal sympathetic nerve activity in muscle is associated with this process. Overall, the relationship between SNS activity and obesity is complex, with evidence of low SNS activity occurring in some, but not all, studies.

Energy balance and brown adipose tissue thermogenesis during chronic endotoxemia in rats

1989 ◽  
Vol 66 (4) ◽  
pp. 1970-1975 ◽  
Author(s):  
J. Arnold ◽  
R. A. Little ◽  
N. J. Rothwell
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Weight Gain ◽  
Energy Balance ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Body Weight Gain ◽  
Male Rats ◽  
Brown Adipose ◽  
Brown Adipose Tissue Thermogenesis

The effects of continuously administered endotoxin on 7-day energy balance were investigated in male rats. Three groups of rats were implanted with osmotic pumps; two groups received saline-filled pumps, whereas the third received endotoxin. One of the saline groups was pair fed to match the food intake of the endotoxemic rats. After 7 days, body energy and protein and fat contents of rats were determined together with the energy content of food and feces. Endotoxin infusion not only induced fever, but it also suppressed appetite and significantly decreased body weight gain. Metabolizable energy intake was reduced by approximately 20% in infected rats. Although protein and fat gains were lowest in the endotoxin group, there appeared to be a selective loss of protein when considered as percent of body weight. Percent body fat was unaltered between the groups. Energy expenditure considered in absolute (kJ) or body weight-independent (kJ/kg0.67) terms yielded similar patterns of results; expenditure (kJ) was 10 and 20% (P less than 0.05, P less than 0.01) lower in the endotoxemic and pair-fed rats, respectively, compared with controls. Hence, compared with pair-fed rats, endotoxin-infused animals had a 10% rise in their expenditure. Brown adipose tissue thermogenesis was assessed by mitochondrial binding of guanosine 5′-diphosphate, and results showed that binding was greatest in endotoxemic rats and lowest in the pair-fed animals. The present results suggest that in this endotoxemic model appetite suppression exacerbates changes in energy balance. However, the reduction in body weight gain is also dependent on a decrease in metabolic efficiency and an increase in total energy expenditure.(ABSTRACT TRUNCATED AT 250 WORDS)

Brown adipose tissue activation in a rat model of Parkinson’s disease

2017 ◽  
Vol 313 (6) ◽  
pp. E731-E736 ◽  
Author(s):  
Wenjuan Wang ◽  
Xiangzhi Meng ◽  
Chun Yang ◽  
Dongliang Fang ◽  
Xuemeng Wang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Weight Loss ◽  
Body Weight ◽  
Adipose Tissue ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Energy Intake ◽  
Rat Model ◽  
Sympathetic Denervation ◽  
Brown Adipose

Loss of body weight and fat mass is one of the nonmotor symptoms of Parkinson’s disease (PD). Weight loss is due primarily to reduced energy intake and increased energy expenditure. Whereas inadequate energy intake in PD patients is caused mainly by appetite loss and impaired gastrointestinal absorption, the underlying mechanisms for increased energy expenditure remain largely unknown. Brown adipose tissue (BAT), a key thermogenic tissue in humans and other mammals, plays an important role in thermoregulation and energy metabolism; however, it has not been tested whether BAT is involved in the negative energy balance in PD. Here, using the 6-hydroxydopamine (6-OHDA) rat model of PD, we found that the activity of sympathetic nerve (SN), the expression of Ucp1 in BAT, and thermogenesis were increased in PD rats. BAT sympathetic denervation blocked sympathetic activity and decreased UCP1 expression in BAT and attenuated the loss of body weight in PD rats. Interestingly, sympathetic denervation of BAT was associated with decreased sympathetic tone and lipolysis in retroperitoneal and epididymal white adipose tissue. Our data suggeste that BAT-mediated thermogenesis may contribute to weight loss in PD.

CNS origins of the sympathetic nervous system outflow to brown adipose tissue

1999 ◽  
Vol 276 (6) ◽  
pp. R1569-R1578 ◽  
Author(s):  
Maryam Bamshad ◽  
C. Kay Song ◽  
Timothy J. Bartness
Keyword(s):  
Nervous System ◽  
Adipose Tissue ◽  
Sympathetic Nervous System ◽  
Brown Adipose Tissue ◽  
Pseudorabies Virus ◽  
Critical Role ◽  
Hypothalamic Nucleus ◽  
Brown Adipose ◽  
Sympathetic Nervous ◽  
Diet Induced Thermogenesis

Brown adipose tissue (BAT) plays a critical role in cold- and diet-induced thermogenesis. Although BAT is densely innervated by the sympathetic nervous system (SNS), little is known about the central nervous system (CNS) origins of this innervation. The purpose of the present experiment was to determine the neuroanatomic chain of functionally connected neurons from the CNS to BAT. A transneuronal viral tract tracer, Bartha’s K strain of the pseudorabies virus (PRV), was injected into the interscapular BAT of Siberian hamsters. The animals were killed 4 and 6 days postinjection, and the infected neurons were visualized by immunocytochemistry. PRV-infected neurons were found in the spinal cord, brain stem, midbrain, and forebrain. The intensity of labeled neurons in the forebrain varied from heavy infections in the medial preoptic area and paraventricular hypothalamic nucleus to few infections in the ventromedial hypothalamic nucleus, with moderate infections in the suprachiasmatic and lateral hypothalamic nuclei. These results define the SNS outflow from the brain to BAT for the first time in any species.

Relationship of brown adipose tissue with growth and obesity differences in genetically selected mouse lines

1984 ◽  
Vol 26 (3) ◽  
pp. 339-347 ◽  
Author(s):  
A. M. Saxton ◽  
E. J. Eisen ◽  
J. M. Leatherwood
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Single Gene ◽  
Tissue Growth ◽  
Growth Patterns ◽  
High Fat ◽  
Polygenic Control ◽  
Brown Adipose ◽  
Diet Induced Thermogenesis

A recent hypothesis considers brown adipose tissue (BAT) to be an important source of diet-induced thermogenesis (DIT). In turn, DIT and thermogenesis in general are believed to be key factors in the control of obesity of laboratory rodents. This hypothesis was developed from the study of single gene mutant obese rodents. The present research tested this hypothesis in mice with polygenic control of growth and obesity, which is more characteristic of the type of genetic variation expected in human and other mammalian populations. Control and high fat diets were used to test responses of five genetically selected lines of mice showing different patterns of growth and obesity. All lines deposited more fat on the high fat diet, but the most obese line showed the largest increase in BAT and the lipid-free dry (LFD) component of BAT. Use of LFD per unit body weight gave results which supported the hypothesis being tested, but it was argued that this measure is misleading. When brown and white adipose tissue growth relative to body weight were examined, 2 of the 10 line – diet groups showed alterations in BAT growth patterns. However, it was concluded that BAT, if involved at all, was not a major factor in growth and obesity differences.Key words: obesity, polygenes, adipose tissue, quantitative inheritance, mouse.

scholarly journals Nicotine Improves Obesity and Hepatic Steatosis and ER Stress in Diet-Induced Obese Male Rats

Endocrinology ◽  
2014 ◽  
Vol 155 (5) ◽  
pp. 1679-1689 ◽  
Author(s):  
Patricia Seoane-Collazo ◽  
Pablo B. Martínez de Morentin ◽  
Johan Fernø ◽  
Carlos Diéguez ◽  
Rubén Nogueiras ◽  
...  
Keyword(s):  
Nervous System ◽  
Body Weight ◽  
Adipose Tissue ◽  
Energy Balance ◽  
Protein Kinase ◽  
Brown Adipose Tissue ◽  
Male Rats ◽  
Brown Adipose ◽  
Brown Adipose Tissue Thermogenesis ◽  
Amp Activated Protein Kinase

Nicotine, the main addictive component of tobacco, promotes body weight reduction in humans and rodents. Recent evidence has suggested that nicotine acts in the central nervous system to modulate energy balance. Specifically, nicotine modulates hypothalamic AMP-activated protein kinase to decrease feeding and to increase brown adipose tissue thermogenesis through the sympathetic nervous system, leading to weight loss. Of note, most of this evidence has been obtained in animal models fed with normal diet or low-fat diet (LFD). However, its effectiveness in obese models remains elusive. Because obesity causes resistance towards many factors involved in energy homeostasis, the aim of this study has been to compare the effect of nicotine in a diet-induced obese (DIO) model, namely rats fed a high-fat diet, with rats fed a LFD. Our data show that chronic peripheral nicotine treatment reduced body weight by decreasing food intake and increasing brown adipose tissue thermogenesis in both LFD and DIO rats. This overall negative energy balance was associated to decreased activation of hypothalamic AMP-activated protein kinase in both models. Furthermore, nicotine improved serum lipid profile, decreased insulin serum levels, as well as reduced steatosis, inflammation, and endoplasmic reticulum stress in the liver of DIO rats but not in LFD rats. Overall, this evidence suggests that nicotine diminishes body weight and improves metabolic disorders linked to DIO and might offer a clear-cut strategy to develop new therapeutic approaches against obesity and its metabolic complications.

scholarly journals Intact innervation is essential for diet-induced recruitment of brown adipose tissue

2019 ◽  
Vol 316 (3) ◽  
pp. E487-E503 ◽  
Author(s):  
Alexander W. Fischer ◽  
Christian Schlein ◽  
Barbara Cannon ◽  
Joerg Heeren ◽  
Jan Nedergaard
Keyword(s):  
Nervous System ◽  
Adipose Tissue ◽  
Food Intake ◽  
Brown Adipose Tissue ◽  
Chow Diet ◽  
Metabolic Efficiency ◽  
Protein Levels ◽  
Brown Adipose ◽  
Ucp1 Expression ◽  
Diet Induced Thermogenesis

The possibility that recruitment and activation of brown adipose tissue (BAT) thermogenesis could be beneficial for curtailing obesity development in humans prompts a need for a better understanding of the control of these processes [that are often referred to collectively as diet-induced thermogenesis (DIT)]. Dietary conditions are associated with large changes in blood-borne factors that could be responsible for BAT recruitment, but BAT is also innervated by the sympathetic nervous system. To examine the significance of the innervation for DIT recruitment, we surgically denervated the largest BAT depot, i.e., the interscapular BAT depot in mice and exposed the mice at thermoneutrality to a high-fat diet versus a chow diet. Denervation led to an alteration in feeding pattern but did not lead to enhanced obesity, but obesity was achieved with a lower food intake, as denervation increased metabolic efficiency. Conclusively, denervation totally abolished the diet-induced increase in total UCP1 protein levels observed in the intact mice, whereas basal UCP1 expression was not dependent on innervation. The denervation of interscapular BAT did not discernably hyper-recruit other BAT depots, and no UCP1 protein could be detected in the principally browning-competent inguinal white adipose tissue depot under any of the examined conditions. We conclude that intact innervation is essential for diet-induced thermogenesis and that circulating factors cannot by themselves initiate recruitment of brown adipose tissue under obesogenic conditions. Therefore, the processes that link food intake and energy storage to activation of the nervous system are those of significance for the further understanding of diet-induced thermogenesis.

scholarly journals Dorsomedial hypothalamic BDNF neurons integrate thermal afferent signals to control energy expenditure

2021 ◽  
Author(s):  
Wei L Shen ◽  
Hongbin Sun ◽  
Qian Zhou ◽  
Hao Bian ◽  
Mengting Wang ◽  
...  
Keyword(s):  
Physical Activity ◽  
Body Weight ◽  
Adipose Tissue ◽  
Weight Gain ◽  
Energy Expenditure ◽  
Body Weight Gain ◽  
Dorsomedial Hypothalamus ◽  
Brown Adipose ◽  
Thermoregulatory System ◽  
Bdnf Signaling

Mutations in the gene brain-derived neurotrophic factor (BDNF) cause obesity in humans. BDNF signaling and its expressing neurons in the hypothalamus help control feeding, energy expenditure (EE), and physical activity. However, whether the BDNF neurons interact with another EE-regulating system, the thermoregulation circuitry, remains unclear. Here, we show that BDNF neurons in the dorsomedial hypothalamus (DMH) are activated by environmental cooling and sufficient to induce body temperature increases and brown adipose tissue (BAT) thermogenesis. Conversely, blocking these neurons impairs BAT thermogenesis and cold defense, causing body weight gain and glucose intolerance. DMH BDNF neurons are therefore an important type of thermoregulatory neuron, integrating thermal afferent signals to control EE during cold defense. This reveals a critical intersection between the BDNF circuitry and the thermoregulatory system.

Increased sensitivity of the genetically obese mouse to corticosterone

1987 ◽  
Vol 252 (2) ◽  
pp. E202-E208 ◽  
Author(s):  
K. Tokuyama ◽  
J. Himms-Hagen
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Weight Gain ◽  
Food Intake ◽  
Brown Adipose Tissue ◽  
Body Weight Gain ◽  
Serum Insulin ◽  
Obese Mouse ◽  
Serum Corticosterone ◽  
Brown Adipose

Adrenalectomy normalizes many abnormalities of the obese (ob/ob) mouse. The high corticosterone concentration in blood may account in part for development of obesity and other abnormalities in the ob/ob mouse. Our objective was to determine dose-response relationships for the effect of corticosterone on the obesity. Lean and ob/ob mice were adrenalectomized or sham-operated at 4.5 wk of age. Adrenalectomized mice received 100 mg implants of cholesterol containing corticosterone (0, 2, 5, 20, or 50 mg) at 8.5 wk of age and were killed at 10.5 wk of age. In ob/ob mice, but not in lean mice, low physiological levels of serum corticosterone (up to 10 micrograms/dl) markedly increased body weight gain, food intake, and serum insulin. They also increased white and brown adipose tissue weights and decreased brown adipose tissue mitochondrial GDP binding. Higher levels of corticosterone (12-22 micrograms/dl) increased body weight gain, white and brown adipose tissue weights, and serum insulin and suppressed brown adipose tissue mitochondrial GDP binding in lean mice also, although in most cases to a lesser extent than in ob/ob mice, but were still without effect on food intake. Only very high levels of corticosterone (approximately 30 micrograms/dl) increased food intake in lean mice. Hyperglycemia was induced in ob/ob, but not lean, mice only at concentrations of corticosterone greater than 17 micrograms/dl. Thermoregulation was unaffected by serum corticosterone at levels from 0 to 30 micrograms/dl in both ob/ob and lean mice. Thus the ob/ob mouse is excessively sensitive and responsive to an effect of physiological levels of corticosterone that results in hyperphagia, hyperinsulinemia, and increased weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of diet and photoperiod on NE turnover and GDP binding in Siberian hamster brown adipose tissue

1986 ◽  
Vol 250 (3) ◽  
pp. R383-R388 ◽  
Author(s):  
J. F. McElroy ◽  
P. W. Mason ◽  
J. M. Hamilton ◽  
G. N. Wade
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Food Intake ◽  
Brown Adipose Tissue ◽  
Turnover Rate ◽  
Siberian Hamsters ◽  
Bat Mitochondria ◽  
Brown Adipose ◽  
Diet Induced Thermogenesis ◽  
Long Photoperiod

This experiment examined the effects of diet and photoperiod on food intake, body weight, and brown adipose tissue (BAT) activity in female Siberian hamsters (Phodopus sungorus sungorus). BAT function was assessed by measuring both the sympathetic nervous system activity of BAT [estimated by the rate of norepinephrine (NE) turnover] and BAT thermogenic activity (estimated by GDP binding to BAT mitochondria). Nineteen weeks of high-fat feeding in long photoperiod [16:8 light-dark cycle (LD)] caused a 20% increase in food intake but did not affect body weight. Both NE turnover rate and GDP binding in interscapular BAT (IBAT) were increased four- to eightfold relative to that from chow-fed controls. Thus it appears that in Siberian hamsters BAT can serve the same energy-dissipating function during diet-induced overeating previously established in rats and mice. Nineteen-week exposure to a short photoperiod (LD 8:16) produced a reduction in body weight but did not affect food intake. Both NE turnover rate and GDP binding in IBAT were increased two- to fourfold relative to that from long-photoperiod controls. Thus it appears that in Siberian hamsters the photoperiod-induced improvements in thermogenic capacity are mediated via the same mechanisms as are cold- or diet-induced thermogenesis.

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