Body Weight Regulation (body + weight_regulation)

Distribution by Scientific Domains

Selected Abstracts

Contributions of the hippocampus and medial prefrontal cortex to energy and body weight regulation

HIPPOCAMPUS, Issue 3 2009
Terry L. Davidson
Abstract The effects of selective ibotenate lesions of the complete hippocampus (CHip), the hippocampal ventral pole (VP), or the medial prefrontal cortex (mPFC) in male rats were assessed on several measures related to energy regulation (i.e., body weight gain, food intake, body adiposity, metabolic activity, general behavioral activity, conditioned appetitive responding). The testing conditions were designed to minimize the nonspecific debilitating effects of these surgeries on intake and body weight. Rats with CHip and VP lesions exhibited significantly greater weight gain and food intake compared with controls. Furthermore, CHip-lesioned rats, but not rats with VP lesions, showed elevated metabolic activity, general activity in the dark phase of the light-dark cycle, and greater conditioned appetitive behavior, compared with control rats without these brain lesions. In contrast, rats with mPFC lesions were not different from controls on any of these measures. These results indicate that hippocampal damage interferes with energy and body weight regulation, perhaps by disrupting higher-order learning and memory processes that contribute to the control of appetitive and consummatory behavior. 2008 Wiley-Liss, Inc. [source]

Specific insulin sensitivity and leptin responses to a nutritional treatment of obesity via a combination of energy restriction and fatty fish intake

I. Abete
Abstract Background, Nutritional strategies to treat obesity often influence neuroendocrine factors related to body weight control. The present study aimed to investigate whether the inclusion of three fatty fish servings per week within a hypocaloric diet may have specific healthy effects on insulin and leptin functions. Methods, Thirty-two subjects (body mass index = 31.6 3.5 kg m,2) aged 36 7 years, were assigned to a control or fish-based energy-restricted diet over an 8-week period. Anthropometry, body composition, lipid profile, leptin and insulin values were measured at the start and at the end of the dietary intervention. Results, Both experimental diets resulted in a similar mean weight loss (control = 5.3 2.6% versus fish-based = 5.5 2.5%; P = 0.783). A significant reduction in insulin resistance, as determined by the homeostatic model assessment index (HOMA-IR = insulin glucose/22.5), was observed after the fish-based intervention. The change in circulating leptin was higher in the fish-based diet compared to the control group. Sixteen percent of the variability in the change of adjusted-leptin could be explained (P = 0.034) by the HOMA index change and the type of diet. Conclusions, Three servings a week of fatty fish included in an energy-restricted diet appears to be a valid strategy for specifically improving insulin sensitivity and leptin levels in obese subjects, which could involve a better body weight regulation after a nutritional intervention period. [source]

The neurobiology and genetics of eating and weight regulation

J. Hebebrand
Over the past 15 years tremendous advances have been made in the elucidation of pathways relevant to eating behaviour and body weight regulation. It has become evident that these pathways are intricately interwoven with those underlying mood and anxiety regulation, motor activity, cognition, sleep, fertility and libido. In addition, advances have been made in determining genetic variation underlying inter-individual differences in body weight. To illustrate these novel findings we will focus on: 1) Monogenic and oligogenic obesity: The underlying genes were initially detected in animal models. Based on mutation screens of the human homologues functionally relevant mutations were detected in the genes coding for leptin, its receptors and the melanocortin-4 receptor (MC4R). The effect of such mutations is large. Leptin gene mutations lead to hyperphagia and subsequently obesity. Hyperphagia, albeit of a substantially reduced magnitude, has also been observed in obese children with mutations in the MC4R. 2) Polygenic obesity: The advent of genome wide association studies has led to the detection of single polygenes, among which FTO features prominently. Typically, a variant predisposing to obesity accounts for a body weight elevated by on average 200 to 1500 grams. Such polygenes act in concert to account for inter-individual differences in body weight. 3) Leptin has been shown to have profound implications for anorexia nervosa. Serum leptin levels in this eating disorders are annormaly low. The hypoleptinemia entails a down-regulation of the hypothalamic-pituitary-gonadal-axis, which underlies the amenorrhea characteristic of anorexia nervosa. Furthermore, the hypoleptinemia induces hyperactivity in a rat model of anorexia nervosa. In patients, leptin levels are inversely correlated with activity levels. [source]

Nonexercise activity thermogenesis , liberating the life-force

J. A. Levine
Abstract Obesity occurs when energy intake exceeds energy expenditure over a protracted period of time. The energy expenditure associated with everyday activity is called NEAT (Nonexercise activity thermogenesis). NEAT varies between two people of similar size by 2000 kcal day,1 because of people's different occupations and leisure-time activities. Data support the central hypothesis that NEAT is pivotal in the regulation of human energy expenditure and body weight regulation and that NEAT is important for understanding the cause and effective treatment for obesity. [source]

Obesity , is it a genetic disorder?

R. J. F. Loos
Abstract., Loos RJF, Bouchard C (Human Genomics Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA). Obesity , is it a genetic disorder? (Review). J Intern Med 2003; 254: 401,425. Obesity is one of the most pressing problems in the industrialized world. Twin, adoption and family studies have shown that genetic factors play a significant role in the pathogenesis of obesity. Rare mutations in humans and model organisms have provided insights into the pathways involved in body weight regulation. Studies of candidate genes indicate that some of the genes involved in pathways regulating energy expenditure and food intake may play a role in the predisposition to obesity. Amongst these genes, sequence variations in the adrenergic receptors, uncoupling proteins, peroxisome proliferator-activated receptor, and the leptin receptor genes are of particular relevance. Results that have been replicated in at least three genome-wide scans suggest that key genes are located on chromosomes 2p, 3q, 5p, 6p, 7q, 10p, 11q, 17p and 20q. We conclude that the currently available evidence suggests four levels of genetic determination of obesity: genetic obesity, strong genetic predisposition, slight genetic predisposition, and genetically resistant. This growing body of research may help in the development of anti-obesity agents and perhaps genetic tests to predict the risk for obesity. [source]

Physical activity, food intake, and body weight regulation: insights from doubly labeled water studies

Klaas R Westerterp
Body weight and energy balance can be maintained by adapting energy intake to changes in energy expenditure and vice versa, whereas short-term changes in energy expenditure are mainly caused by physical activity. This review investigates whether physical activity is affected by over- and undereating, whether intake is affected by an increase or a decrease in physical activity, and whether being overweight affects physical activity. The available evidence is based largely on studies that quantified physical activity with doubly labeled water. Overeating does not affect physical activity, while undereating decreases habitual or voluntary physical activity. Thus, it is easier to gain weight than to lose weight. An exercise-induced increase in energy requirement is typically compensated by increased energy intake, while a change to a more sedentary routine does not induce an equivalent reduction of intake and generally results in weight gain. Overweight and obese subjects tend to have similar activity energy expenditures to lean people despite being more sedentary. There are two ways in which the general population trend towards increasing body weight can be reversed: reduce intake or increase physical activity. The results of the present literature review indicate that eating less is the most effective method for preventing weight gain, despite the potential for a negative effect on physical activity when a negative energy balance is reached. [source]

The role of the glycaemic index of foods in body weight regulation and obesity.

Is more evidence needed?

Polymorphisms in the STAT6 gene and their association with carcass traits in feedlot cattle

G. Rincon
Summary Identification of the genes and polymorphisms underlying quantitative traits, and understanding how these genes and polymorphisms affect economic traits, are important for successful marker-assisted selection and more efficient management strategies in commercial cattle populations. Signal transducer and activator of transcription 6 (STAT6) gene is tightly connected to IL-4 and IL-13 signalling and plays a key role in TH2 polarization of the immune system. In addition, STAT6 acts as a mediator of leptin signalling and has been associated with body weight regulation. The objective of this study was to determine if SNPs within the bovine STAT6 gene are associated with economically important traits in feedlot cattle. The approach consisted of resequencing STAT6 using a panel of DNA from unrelated animals of different beef breeds. Specifically, 16 kb of STAT6 was resequenced in 47 animals and the process revealed 39 SNPs. From the 39 SNPs, a panel of 15 tag SNPs was genotyped in 1500 beef cattle samples with phenotypes to perform a marker-trait association analysis. Among the 15 tag SNPs, five and six were polymorphic in Bos taurus and Bos indicus respectively. An association analysis was performed between the 15 tag SNPs and 14 performance and production traits. SNP ss115492459:C > A, ss115492461:A > G and ss115492458:G > C were significantly associated with back fat, calculated yield grade, cutability, hot carcass weight, dry matter intake, days on feed, back fat rate and average daily gain. These three SNPs were present in all Bos taurus beef breeds examined. Our results provide evidence that polymorphisms in STAT6 are associated with carcass and growth efficiency traits, and may be used for marker-assisted selection and management in feedlot cattle. [source]

Adiponectin, ghrelin, and leptin in cancer cachexia in breast and colon cancer patients

CANCER, Issue 4 2006
Ido Wolf M.D.
Abstract BACKGROUND The hormone ghrelin and the adipocytokines leptin and adiponectin participate in body weight regulation. In response to weight loss, ghrelin and adiponectin levels increase and leptin decreases. Cancer cachexia is a complex metabolic state, characterized by loss of muscle mass and adipose tissue together with anorexia. The authors hypothesized that responses of these hormones may be attenuated in cancer cachexia. METHODS Fasting plasma ghrelin, adiponectin, and leptin levels, as well as weight loss, were determined in 40 cancer patients: 18 of them suffered from cancer-induced cachexia, and 22 served as a comparison group. Hormone levels were measured before administration of cancer therapy. RESULTS A similar distribution of age, gender, and diagnosis was observed in both study groups, but the cachectic patients had higher rates of metastatic disease and lower albumin levels. No significant correlation was observed between plasma adiponectin levels and weight loss. Mean plasma ghrelin levels were higher among cachectic compared with noncachectic patients. Notably, the association between ghrelin levels and weight loss was only modest, and in a third of the cachectic patients, ghrelin levels were equal to or lower than those in the noncachectic group. Plasma leptin levels showed gender-dependent associations, and significantly lower levels were found among cachectic women but not among cachectic men. CONCLUSIONS Results suggested a gender-dependent attenuation of expected physiologic responses to weight loss among cancer cachexia patients. Thus, impaired response of adiponectin, ghrelin, and leptin may play a role in the pathogenesis of cancer cachexia syndrome. Cancer 2006. 2006 American Cancer Society. [source]