Defense of body weight against chronic caloric restriction in obesity-prone and -resistant rats

2000 ◽  
Vol 278 (1) ◽  
pp. R231-R237 ◽  
Author(s):  
Barry E. Levin ◽  
Ambrose A. Dunn-Meynell
Keyword(s):  
Caloric Restriction ◽  
High Energy ◽  
The Body ◽  
Male Rats ◽  
Sprague Dawley ◽  
Insulin Levels ◽  
Sprague Dawley Rats ◽  
Body Weights ◽  
Plasma Leptin ◽  
Adipose Mass

Half of Sprague-Dawley rats develop and defend diet-induced obesity (DIO) or diet resistance (DR) when fed a high-energy (HE) diet. Here, adult male rats were made DIO or DR after 10 wk on HE diet. Then half of each group was food restricted for 8 wk on chow to maintain their body weights at 90% of their respective baselines. Rate and magnitude of weight loss were comparable, but maintenance energy intake and the degree of sympathetic activity (24-h urine norepinephrine) inhibition were 17 and 29% lower, respectively, in restricted DR than DIO rats. Restricted DIO rats reduced adipose depot weights, plasma leptin, and insulin levels by 35%. Restricted DR rats reduced none of these. When fed ad libitum, both DR and DIO rats returned to the body weights of their respective chow-fed phenotype controls within 2 wk. This was associated with increased adipose mass and leptin and insulin levels only in DIO rats. Thus DR rats appear to alter primarily their lean body mass, whereas DIO rats primarily alter their adipose mass during chronic caloric restriction and refeeding.

A new obesity-prone, glucose-intolerant rat strain (F.DIO)

2003 ◽  
Vol 285 (5) ◽  
pp. R1184-R1191 ◽  
Author(s):  
Barry E. Levin ◽  
Ambrose A. Dunn-Meynell ◽  
Julie E. McMinn ◽  
Michael Alperovich ◽  
Amy Cunningham-Bussel ◽  
...  
Keyword(s):  
Insulin Response ◽  
High Energy ◽  
Male Rats ◽  
Oral Glucose ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Rat Strain ◽  
Plasma Leptin ◽  
F344 Rats ◽  
Mode Of Inheritance

Previous breeding for the diet-induced obese (DIO) trait from outbred Sprague-Dawley rats produced a substrain with selection characteristics suggesting a polygenic mode of inheritance. To assess this issue further, selectively bred DIO male rats were crossed with obesity-resistant inbred Fischer F344 dams. Male offspring were crossed twice more against female F344 dams. The resultant N3 (F.DIO) rats were then inbred three more times. On low-fat chow, 10-wk-old male and female DIO rats weighed 86 and 59% more than respective F344 rats. By the N3 (F.DIO) generation, they were only 12 and 10% heavier, respectively. After three additional inbreeding cycles, chow-fed F.DIO males had an exaggerated insulin response to oral glucose compared with F344 rats. After 3 wk on a 31% fat (high-energy) diet, male N3 F.DIO rats gained 16-20% more carcass and adipose weight with 98% higher plasma leptin levels, whereas F.DIO females gained 36-54% more carcass and adipose weight with 130% higher leptin levels than comparable F344 rats. After three inbreeding cycles, F.DIO males still gained more weight on high-energy diet and developed a threefold greater insulin response to oral glucose than F344 males. Preservation of the DIO and glucose intolerance traits through successive backcrosses and inbreeding cycles to produce the F.DIO strain lends further support to the idea that they inherited in a polygenic fashion.

Defense of differfing body weight set points in diet-induced obese and resistant rats

1998 ◽  
Vol 274 (2) ◽  
pp. R412-R419 ◽  
Author(s):  
Barry E. Levin ◽  
Richard E. Keesey
Keyword(s):  
Body Weight ◽  
Diet Composition ◽  
Energy Homeostasis ◽  
Energy Content ◽  
Sprague Dawley ◽  
Fat Pad ◽  
Insulin Levels ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Plasma Leptin

Among outbred Sprague-Dawley rats, approximately one-half develop diet-induced obesity (DIO) and one-half are diet resistant (DR) on a diet relatively high in fat and energy content (HE diet). Here we examined the defense of body weight in these two phenotypes. After HE diet for 13 wk, followed by chow for 6 wk, DR rats gained weight comparably but their plasma leptin levels fell to 54% of chow-fed controls. When a palatable liquid diet (Ensure) was added for 13 wk, other DR rats became obese. But when switched to chow, their intakes fell by 60%, and body and retroperitoneal (RP) fat pad weights and plasma leptin and insulin levels all declined for 2 wk and then stabilized at control levels after 6 wk. In contrast, comparably obese DIO rats decreased their intake by only 20%, and their weights plateaued when they were switched to chow after 13 wk on HE diet. When a subgroup of these DIO rats was restricted to 60% of prior intake, their weights fell to chow-fed control levels over 2 wk. But their leptin and insulin levels both fell disproportionately to 30% of controls. When no longer restricted, their intake and feed efficiency rose immediately, and their body and RP pad weights and leptin and insulin levels rose to those of unrestricted DIO rats within 2 wk. Thus diet and genetic background interact to establish high (DIO) or low (DR) body weight set points, which are then defended against subsequent changes in diet composition and/or energy availability. If leptin affects energy homeostasis, it does so differentially in DIO vs. DR rats since comparably low and high levels were associated with differing patterns of weight change between the two phenotypes.

Ontogeny of diet-induced obesity in selectively bred Sprague-Dawley rats

2003 ◽  
Vol 285 (3) ◽  
pp. R610-R618 ◽  
Author(s):  
Matthew R. Ricci ◽  
Barry E. Levin
Keyword(s):  
Leptin Receptor ◽  
Splice Variants ◽  
Caloric Intake ◽  
High Energy ◽  
Sprague Dawley ◽  
Low Fat Diet ◽  
Diet Induced Obesity ◽  
Leptin Sensitivity ◽  
Sprague Dawley Rats ◽  
Plasma Leptin

Outbred Sprague-Dawley rats selectively bred for their propensity to develop diet-induced obesity (DIO) become heavier on low-fat diet than those bred to be diet resistant (DR) beginning at ∼5 wk of age. Here we assessed the development of metabolic and neural functions for insights into the origins of their greater weight gain. From week 5 to week 10, chow-fed DIO rats gained 15% more body weight and ate ∼14% more calories but had only slightly greater adiposity and plasma leptin than DR rats. From day 3 through week 10, DIO and DR rats had similar mRNA expression of arcuate nucleus neuropeptide Y, proopiomelanocortin, agouti-related peptide, and all splice variants of the leptin receptor (OB-R). When fed a high-energy (HE; 31% fat) diet, 7-wk-old DIO rats had a 240% increase in plasma leptin levels after only 3 days. Despite this early leptin rise, they maintained a persistent hyperphagia and became more obese than chow-fed DIO rats and DR rats fed chow or HE diet. Their failure to reduce caloric intake, despite high levels of leptin, suggests that selectively bred DIO rats might have reduced leptin sensitivity similar to that seen in the outbred DIO parent strain.

Initiation and perpetuation of obesity and obesity resistance in rats

1989 ◽  
Vol 256 (3) ◽  
pp. R766-R771 ◽  
Author(s):  
B. E. Levin ◽  
S. Hogan ◽  
A. C. Sullivan
Keyword(s):  
High Energy ◽  
The Body ◽  
Sprague Dawley ◽  
Fat Pad ◽  
Intravenous Glucose ◽  
Insulin Resistant ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Fat Pads

A search was made for predisposing factors and sequelae of diet-induced obesity (DIO) or resistance to DIO (DR). During 3 mo on a high-energy (CM) diet, two-thirds of the male Sprague-Dawley rats ate 16% more calories over the first 30 days and developed DIO. The remaining one-third were DR, gaining the same amount of weight as chow-fed controls. Basal and norepinephrine (NE)-stimulated in vivo O2 consumption, performed before rats were placed on the CM diet, was the same in those rats that later became DR or DIO after 3 mo on the CM diet. DR rats were 4% lighter, whereas DIO rats were equal to chow-fed rats before their exposure to the CM diet. When CM-fed rats were switched to chow, DIO rats took 14 wk to reduce their body and retroperitoneal fat pad weights to those of chow-fed controls, whereas DR rats gained only 40% of the body weight, and fat pads were 34% lighter than controls. After 14 wk, DIO rats were neither hyperinsulinemic nor insulin resistant, whereas DR rats had 64% reduced areas under their insulin curves after intravenous glucose (1 g/kg) compared with controls. Unlike younger rats, animals here had inconsistent plasma NE responses to intravenous glucose. Therefore the CM diet produces DR and DIO states that tend to become self-perpetuating once established.

Diet cycling and age alter weight gain and insulin levels in rats

1994 ◽  
Vol 267 (2) ◽  
pp. R527-R535 ◽  
Author(s):  
B. E. Levin
Keyword(s):  
Weight Gain ◽  
Body Weight Gain ◽  
High Energy ◽  
Sprague Dawley ◽  
Insulin Levels ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Plasma Insulin Levels ◽  
Diet Intake

For assessment of the effect of diet cycling on body weight gain patterns, 3-mo-old male Sprague-Dawley rats were either cycled from chow to a high-energy condensed milk (CM) diet, back to chow, and then back to CM diet at 3-mo intervals (cyclers) or were fed chow to 9 mo of age and then CM diet for 3 mo (noncyclers). Nine of 21 cyclers developed diet-induced obesity (DIO), gaining 36, 59, and 281% more weight than chow-fed controls (CF) at each cycle, respectively. Twelve cycled rats were diet-resistant (DR) with comparable weight gain to CF rats after the first CM diet and chow cycles. However, they gained 202% more than CF rats and 50% more, with 29% heavier retroperitoneal fat pads, than noncycled DR rats after their second CM diet cycle begun at 9 mo of age. Enhanced weight gain in DR cyclers was probably due to enhanced food efficiency in the last few weeks of CM diet intake. Plasma insulin levels were 70% higher in cycled vs. noncycled DIO and DR rats, and both were higher than CF rats. Unlike 6-mo-old DR rats in a prior study, 12-mo-old noncycled DR rats after 3 mo on CM diet here had 45-172% higher alpha 2-adrenoceptors binding in 6 of 17 brain areas than noncycled DIO and/or CF rats. Thus age, diet cycling, and brain alpha 2-adrenoceptors interact to affect long-term changes in weight gain and metabolism.

scholarly journals Defense of body weight depends on dietary composition and palatability in rats with diet-induced obesity

2002 ◽  
Vol 282 (1) ◽  
pp. R46-R54 ◽  
Author(s):  
Barry E. Levin ◽  
Ambrose A. Dunn-Meynell
Keyword(s):  
Body Weight ◽  
Energy Content ◽  
Selective Reduction ◽  
High Energy ◽  
Hypothalamic Nucleus ◽  
Sprague Dawley ◽  
Diet Induced Obesity ◽  
Background Diet ◽  
Sprague Dawley Rats ◽  
Body Weights

Sprague-Dawley rats selectively bred for diet-induced obesity (DIO) or diet resistance (DR) were characterized on diets of differing energy content and palatability. Over 10 wk, DR rats on a high-energy (HE) diet (31% fat) gained weight similarly to DR rats fed chow (4.5% fat), but they became obese on a palatable liquid diet (Ensure). DIO rats gained 22% more weight on an HE diet and 50% more on Ensure than chow-fed DIO rats. DIO body weight gains plateaued when switched from HE diet to chow. But, Ensure-fed DIO rats switched to chow spontaneously reduced their intake and weight to that of rats switched from HE diet to chow. They also reduced their hypothalamic proopiomelanocortin and dynorphin but not neuropeptide Y mRNA expression by 17–40%. When reexposed to Ensure after 7 wk, they again overate and matched their body weights to rats maintained on Ensure throughout. All Ensure-fed rats had a selective reduction in dynorphin mRNA in the ventromedial hypothalamic nucleus. Thus genetic background, diet composition, and palatability interact to produce disparate levels of defended body weight and central neuropeptide expression.

Effect of physical training on insulin response to intravenous glucose in male peripubertal rats

1992 ◽  
Vol 73 (4) ◽  
pp. 1227-1231 ◽  
Author(s):  
J. Bongbele ◽  
A. Gutierrez ◽  
S. Cardin ◽  
J. M. Lavoie
Keyword(s):  
Glucose Tolerance ◽  
Body Weight Gain ◽  
Insulin Response ◽  
Exercise Bout ◽  
Male Rats ◽  
Sprague Dawley ◽  
Intravenous Glucose ◽  
Sprague Dawley Rats ◽  
Body Weights ◽  
Intravenous Glucose Tolerance Tests

This study was undertaken to evaluate the effects of regular endurance-type exercise (i.e., swimming) on glucose tolerance and glucose-stimulated insulin response (GSIR) in 55- and 90-day-old peripubertal male rats. Intravenous glucose tolerance tests (0.5 g/kg) were done in four groups of male Sprague-Dawley rats: two groups of trained (TR; 55- and 90-day-old) and two groups of age- and weight-matched untrained (UNTR) rats. The UNTR rats were subjected to a continuous food restriction to maintain body weights equal to those of the TR rats. Rats were received in our laboratory after weaning at 21 days of age and were evaluated 48 h after the last exercise bout. No significant differences in body weights were found between TR and UNTR rats, at the age of either 55 or 90 days. A significant (P < 0.01) decrease in the mean integrated area under the glucose and insulin curves was observed in TR compared with UNTR groups in 55- as well as 90-day-old rats. These results indicate that exercise training in male rats improves the glucose tolerance and GSIR before and during puberty (21–90 days) independently of a reduction in body weight gain.

scholarly journals Evaluation of acute and sub-acute oral toxicity of the aqueous extract of Aquilaria malaccensis leaves in Sprague Dawley rats

2019 ◽  
pp. 20-32
Author(s):  
Redzuan Nul Hakim Abdul Razak ◽  
Suzanah Abdul Rahman ◽  
Asmah Hanim Hamdan ◽  
Roszaman Ramli ◽  
Muhammad Lokman Md Isa ◽  
...  
Keyword(s):  
Body Weight ◽  
Acute Toxicity ◽  
Lethal Dose ◽  
The Body ◽  
Female Rats ◽  
Male Rats ◽  
Histopathological Analysis ◽  
Sprague Dawley ◽  
Aquilaria Malaccensis ◽  
Sprague Dawley Rats

Aquilaria malaccensis or commonly known as ‘gaharu’ is a species of Aquilaria genus and belongs to the Thymelaeaceae family. It is widely distributed in Malaysia, Indonesia, and the Borneo Islands. Traditionally, its leaves were used to relieve bruises and studies have shown that they function as an antioxidant, aphrodisiac, and tranquilizer. Despite its proven beneficial medicinal properties, information regarding its toxicity is limited. Therefore, we performed a safety evaluation on the aqueous A. malaccensis leaves extract (AMAE) in Sprague Dawley rats. The assessment of acute toxicity based on the Organization for Economic Cooperation and Development (OECD) Guideline 420 revealed that AMAE did not influence mortality, clinical appearance, body weight gain, or necropsy findings at a dose of 2000 mg/kg body weight. In the sub-acute toxicity, all doses did not significantly modify the body weight and food and water intake. In male rats treated with 2000 mg/kg, there was a significant reduction in the relative weight of liver. Not only that, an increase in alkaline phosphatase and alanine transaminase was also observed in different groups among the female rats. A significant decrease in the creatinine level was also seen among male rats administered with different doses of AMAE. In both sexes, histopathological analysis had shown abnormalities in the liver and kidney of rats treated at the dose of 2000 mg/kg. In conclusion, the 50% lethal dose (LD50) of AMAE was estimated to be greater than 2000 mg/kg. In sub-acute duration, the findings suggested that AMAE administered orally is slightly toxic at higher doses (2000 mg/kg) and could provoke functional and structural changes in the kidney and liver of rats. Thus, the extract should be used with caution.

Acute insulin-induced elevations of circulating leptin and feeding inhibition in lean but not obese rats

2005 ◽  
Vol 289 (2) ◽  
pp. R373-R379 ◽  
Author(s):  
Kimberly A. Singh ◽  
Carol N. Boozer ◽  
Joseph R. Vasselli
Keyword(s):  
Sprague Dawley ◽  
Short Term ◽  
Feeding Inhibition ◽  
Fasted State ◽  
Sprague Dawley Rats ◽  
Or Groups ◽  
Body Weights ◽  
Obese Rats ◽  
Rat Adipose Tissue ◽  
Plasma Leptin

Insulin has been shown to stimulate leptin mRNA expression acutely in rat adipose tissue, but its short-term effects on circulating leptin levels, and subsequent feeding behavior, have not been well described. We used 11-mo-old female selectively bred obesity-resistant (OR) and obesity-prone (OP) Sprague-Dawley rats maintained on laboratory chow to investigate this question. At testing, body weights and basal leptin levels of the OP rats were significantly elevated compared with the OR rats. In the 3-h fasted state, injection of 2.0 U insulin/kg ip resulted in significant elevations of plasma leptin at 4 h postinjection in both OP and OR groups ( hour 4, +2.50 and +5.98 ng/ml, respectively). In separate feeding tests with the same groups, intake of laboratory chow pellets was significantly inhibited during hours 2–4 after 2.0 U/kg of insulin in the OR (−80.1%, P < 0.05), but not in the OP group, compared with intake after saline injections. In feeding tests with palatable moderately high-fat pellets after 2.0 and 3.0 U insulin/kg ip, significant decreases between hours 2 and 4 in intake were seen in the OR group only (−41.0 and −68.3%, respectively). Thus feeding inhibition coincides with insulin-induced elevations of plasma leptin in lean but not obese Sprague-Dawley rats. Our data suggest that elevations of leptin within the physiological range may contribute to short-term inhibition of food intake in rats and that this process may be stimulated by feeding-related insulin release.

scholarly journals Pulmonary Responses of Sprague-Dawley Rats in Single Inhalation Exposure to Graphene Oxide Nanomaterials

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Sung Gu Han ◽  
Jin Kwon Kim ◽  
Jae Hoon Shin ◽  
Joo Hwan Hwang ◽  
Jong Seong Lee ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Histopathological Examination ◽  
Inhalation Exposure ◽  
The Body ◽  
Inhalation Technique ◽  
Sprague Dawley ◽  
High Concentration ◽  
Rat Lungs ◽  
Sprague Dawley Rats ◽  
Body Weights

Graphene is receiving increased attention due to its potential widespread applications in future. However, the health effects of graphene have not yet been well studied. Therefore, this study examined the pulmonary effects of graphene oxide using male Sprague-Dawley rats and a single 6-hour nose-only inhalation technique. Following the exposure, the rats were allowed to recover for 1 day, 7 days, or 14 days. A total of three groups were compared: control (fresh air), low concentration (0.46±0.06 mg/m3), and high concentration (3.76±0.24 mg/m3). The exposure to graphene oxide did not induce significant changes in the body weights, organ weights, and food consumption during the 14 days of recovery time. The microalbumin and lactate dehydrogenase levels in the bronchoalveolar lavage (BAL) fluid were not significantly changed due to the exposure. Similarly, total cell count, macrophages, polymorphonuclear leukocytes, and lymphocytes were not significantly altered in the BAL fluid. Plus, the histopathological examination of the rat lungs only showed an uptake of graphene oxide in the alveolar macrophages of the high-concentration group. Therefore, these results demonstrate that the single inhalation exposure to graphene oxide induce minimal toxic responses in rat lungs at the concentrations and time points used in the present study.

Sign in / Sign up

Export Citation Format

Share Document