Effects of beta-chlornaltrexamine on food intake, body weight and opioid-induced feeding

beta-Chlornaltrexamine (beta-CNA) is a non-equilibrium opioid receptor antagonist which alkylates and inactivates opioid receptors. Because opioid peptides are thought to contribute to the regulation of food intake, we examined the effects of intracerebroventricular (icv) injections of beta-CNA on the food intake and body weight of male rats. We also tested the ability of beta-CNA to block food intake stimulated by selective agonists of kappa, mu and delta opioid receptors: dynorphin A2 (DYN), Tyr-D-Ala-Gly-(Me)Phe-Gly-ol (DAGO), and [(D-Ser2,Leu5]-enkephalin-Thr6 (DSLET). Treatment with beta-CNA caused a long-term (2-4 days) reduction in daily food intake and a concomitant reduction in body weight. An additional experiment indicated that the weight loss after beta-CNA treatment could be completely accounted for by the reduction in intake. beta-CNA treatment also abolished or greatly attenuated the feeding effects of DAGO, DSLET and DYN, even when these peptides were tested 26 hours after beta-CNA administration. The long duration of the effects of beta-CNA suggests that this compound will be a useful pharmacological tool in further study of the opioid feeding system.     

Normal feeding behavior, body weight and leptin response require the neuropeptide Y Y2 receptor.

Neuropeptide Y (NPY), a 36-amino-acid peptide widely expressed in the brain is involved in many physiological responses, including hypothalamic control of food intake and cardiovascular homeostasis. NPY mediates its effects through binding to the Y1, Y2 and Y5 G-protein-coupled receptors. Little is known of the role of the Y2 receptor in mediating the different NPY effects. We inactivated the Y2 receptor subtype in mice and found that these mice developed increased body weight, food intake and fat deposition. The null mutant mice showed an attenuated response to leptin administration but a normal response to NPY-induced food intake and intact regulation of re-feeding and body weight after starvation. An absence of the Y2 receptor subtype also affected the basal control of heart rate, but did not influence blood pressure. These findings indicate an inhibitory role for the Y2 receptor subtype in the central regulation of body weight and control of food intake.     

A role for the adult fat body in Drosophila male courtship behavior

Mating behavior in Drosophila depends critically on the sexual identity of specific regions in the brain, but several studies have identified courtship genes that express products only outside the nervous system. Although these genes are each active in a variety of non-neuronal cell types, they are all prominently expressed in the adult fat body, suggesting an important role for this tissue in behavior. To test its role in male courtship, fat body was feminized using the highly specific Larval serum protein promoter. We report here that the specific feminization of this tissue strongly reduces the competence of males to perform courtship. This effect is limited to the fat body of sexually mature adults as the feminization of larval fat body that normally persists in young adults does not affect mating. We propose that feminization of fat body affects the synthesis of male-specific secreted circulating proteins that influence the central nervous system. In support of this idea, we demonstrate that Takeout, a protein known to influence mating, is present in the hemolymph of adult males but not females and acts as a secreted protein.     

Function of courtship feeding in the Bull-headed Shrike,Lanius bucephalus

We investigated the frequency of courtship feeding (CF) in the Bull-headed Shrike (Lanius bucephalus) during the 1981–1982 breeding seasons. Because no CF was observed just prior to, during or just after copulation, CF is not associated directly with copulation and does not function as a releaser for copulation. The absence of CF during the pair-formation period of the early breeder and the high frequency of CF behavior in the cold season and in the critical breeding stages (egg-laying and incubation stages) for females strongly suggests that the significance of CF in this species is not symbolic but substantial at least in early breeders. We assign one of the causes of this CF to the early onset of breeding.     

Effects of nicotine on body weight, food consumption and body composition in male rats

The present study examined the effects of nicotine administration and cessation on body weight, food consumption, and body composition in rats. Administration of nicotine was associated with attenuated body weight gains and cessation was associated with accelerated body weight gains. Changes in fat composition paralleled changes in body weight, whereas changes in body water and protein did not. These results suggest that nicotine administration decreases body weight through its effects on fat stores in the body. After cessation of nicotine, body fat rapidly approached levels of control animals.     

Effects of food texture change on metabolic parameters: short- and long-term feeding patterns and body weight

A complete diet was prepared with cooked pieces of meat, beans, cream starch, and water and presented to the rats in two different textures: a blended purée and a rough mixture that required a lot of chewing. We hypothesized that this texture modification might change both anticipatory reflexes and feeding behavior. Feeding rate, meal size, intermeal intervals, and their correlation were monitored in response to each texture. The long-term (6 wk) effect on body weight was assessed. Periprandial plasma glucose, insulin, glucagon, and lipid concentrations were assayed. Whole and background metabolism, respiratory quotient, and locomotion were measured using a computerized calorimeter of original design. In the short term, rats preferred the mixture. However, after 3 wk, they ingested more purée than mixture and gained more body weight per gram of food ingested as purée. Insulin response declined earlier with the mixture. During meals, glycerol and free fatty acid increased earlier with purée, whereas in the postprandial period, glycerol increased earlier with mixture. The metabolic rate, however, was not significantly affected. We concluded that texture, an everyday manipulation performed on food for human consumption, affects not only palatability of ingestants but also their metabolic management in the short and long term.     

Modulatory role of food, feeding regime and physical exercise on body weight and insulin resistance

Energy intake and expenditure is a highly conserved and well-controlled system with a bias toward energy intake. In times of abundant food supply, individuals tend to overeat and in consequence to increase body weight, sometimes to the point of clinical obesity. Obesity is a disease that is not only characterized by enormous body weight but also by rising morbidity for diabetes type II and cardiovascular complications. To better understand the critical factors contributing to obesity we performed the present study in which the effects of energy expenditure and energy intake were examined with respect to body weight, localization of fat and insulin resistance in normal Wistar rats. It was found that a diet rich in fat and carbohydrates similar to "fast food" (cafeteria diet) has pronounced implication in the development of obesity, leading to significant body weight gain, fat deposition and also insulin resistance. Furthermore, an irregularly presented cafeteria diet (yoyo diet) has similar effects on body weight and fat deposition. However, these rats were not resistant to insulin, but showed an increased insulin secretion in response to glucose. When rats were fed with a specified high fat/carbohydrate diet (10% fat, 56.7% carbohydrate) ad lib or at the beginning of their activity phase they were able to detect the energy content of the food and compensate this by a lower intake. They, however, failed to compensate when food was given in the resting phase and gained more body weight as controls. Exercise, even of short duration, was able to keep rats on lower body weight and reduced fat deposition. Thus, inappropriate food intake with different levels of energy content is able to induce obesity in normal rats with additional metabolic changes that can be also observed in humans.     

Effects of diverse androgens on the sexual behavior and morphology of castrated male quail

Castrated male Japanese quail were injected for 15 days with 1 mg/day of testosterone propionate (TP), testosterone (T), androstenedione (AE), androsterone (AO), 5α-dihydrotestosterone benzoate (5α-DHTB), or 5β-dihydrotestosterone (5β-DHT), or with oil. Copulation was activated to a significant extent only by TP and T. Strutting was activated only by TP, T, and AE. Proctodeal (foam) glands were well-developed in birds injected with TP, T, AE, or 5α-DHTB. Additional data were obtained following implantation of pellets of crystalline T, AE, AO, or 5α-DHT. T pellets activated copulation, but AO and 5α-DHT pellets did not. Effects of AE require further study. These results suggest that conversion of androgen to estrogen is necessary for the activation of copulation in the male quail.     

凹唇壁蜂成蜂体重与取食对其飞行能力的影响

凹唇壁蜂Osmia excavata Alfken被广泛应用于我国北方果树的传粉, 而其飞行能力是影响其传粉效率的重要因素。本研究通过飞行磨吊飞试验, 评估了凹唇壁蜂雌蜂和雄蜂飞行能力的差异以及取食对其飞行能力的影响。结果表明, 凹唇壁蜂雌蜂体重（116.30 mg）显著大于雄蜂（59.80 mg） (P<0.001), 雌蜂的最大飞行速度（3.44 km/h）显著大于雄蜂（2.36 km/h）, 雄蜂的飞行距离和最大飞行速度与其飞行前体重成显著的正相关性, 雌蜂的飞行时间与其飞行前体重成显著正相关性, 而雌蜂的平均飞行速度与其体重成显著负相关性; 雌蜂的日平均飞行距离为0.23 km, 根据雌蜂以巢为中心, 采集花粉繁殖后代的生物学习性, 蜂巢之间的放置距离应少于100 m。取食蜂蜜后, 雌雄壁蜂的飞行距离、 飞行时间、 最大飞行速度均有提高的趋势, 建议在田间应用时, 可在蜂巢附近放置蜂蜜或种植其他蜜源植物给初羽化的凹唇壁蜂提供食物补充能量。本研究明确了雌、 雄壁蜂的飞行能力和出茧后补充食物对于壁蜂飞行的促进作用, 为有效地利用凹唇壁蜂进行传粉提供了理论依据。     

A role for pancreatic polypeptide in feeding and body weight regulation

PP administration induces negative energy balance by suppressing food intake and gastric emptying while increasing energy expenditure in rodents. The mechanism of PP actions involves the changes in the expression of hypothalamic feeding-regulatory peptides and the activity of the vago-vagal and vago-sympathetic reflex arc. PP-overexpressing mice we developed exhibited the thin phenotype with decreased food intake and gastric emptying rate. Plasma cholecystokinin (CCK) concentrations were increased in the transgenic mice and CCK-1 receptor antagonist improved the anorexia of the animals. These results, together with the previous notion of PP as an anti-CCK hormone in pancreatic exocrine secretion and gallbladder contraction, indicate that PP-CCK interactions may be either antagonistic or synergistic and the transgenic mice may exhibit the mixed phenotype by overproduction of PP and CCK.     

Impact of changes in relationship status on smoking behavior and body weight

This paper examines whether and how changes in relationship status (i.e., cohabitation, marriage, separation, or divorce) affect individuals’ smoking behavior and body weight. Using German Socio-Economic Panel data, this study accounts for differences between treated (i.e., those affected by a specific family event) and untreated participants since treatment and control groups differ with respect to several characteristics such as age, which may bias the results. Therefore, regression-adjusted matching is employed for each family event separately. This study, thus, takes steps towards disentangling causality from correlation. Overall, changes in family composition (such as moving together with or separating from the partner) impact the probability to start or quit smoking and lead to changes in body weight. In particular, smoking behavior and body weight are predominantly affected by forming or dissolving a household, rather than by marriage or divorce: cohabitation leads to weight gain; separation from a partner leads to weight loss, increased smoking initiation, and decreased smoking cessation.     

Geomagnetic field absence reduces adult body weight of a migratory insect by disrupting feeding behavior and appetite regulation

The geomagnetic field(GMF)is well documented for its essential role as a cue used in animal orientation or navigation.Recent evidence indicates that the absence...     

Effects of artificial sweeteners on body weight, food and drink intake

Artificial sweeteners are widely used all over the world. They may assist in weight management, prevention of dental caries, control of blood glucose of diabetics, and also can be used to replace sugar in foods. In the animal experimentation mice were given oral doses of water solutions of table top artificial sweeteners (saccharin, cyclamate based, acesulfame-K based, and aspartame) the amount of maximum Acceptable Daily Intake (ADI) ad libitum. The controls received only tap water with the same drinking conditions as the treated groups. The mice were fed chow ad libitum.We measured food intake and body weight once a week, water and solutions of artificial sweeteners intake twice a week. The data were analysed by statistical methods (T-probe, regression analysis).Consumption of sweeteners resulted in significantly increased body weight; however, the food intake did not change.These results question the effect of non-caloric artificial sweeteners on weight-maintenance or body weight decrease.