Effects of Diet and Time of the Day on Serum and CSF Leptin Levels in Osborne‐Mendel and S5B/Pl Rats

Ishihara, Yuri; White, Christy L.; Kageyama, Haruaki; Kageyama, Asako; York, David A.; Bray, George A.

doi:10.1038/oby.2004.134

Cited by 20 publications

(12 citation statements)

References 49 publications

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“…By contrast, Lin et al (37) reported that Osbourne Mendel rats were resistant to peripheral injections of leptin after only 5 days on a 56% kcal fat diet (37). The reason for the rapid onset of resistance in this study may be associated with the obesity-prone Osbourne Mendel rats, which are relatively leptin resistant even on a LFD (26). The cause of leptin resistance in HFD-fed rats and mice has been associated with a downregulation of leptin receptors (39) and increased expression of suppressor of cytokine signaling 3 (15,62) and protein tyrosine phosphatase 1B (69), both of which inhibit leptin receptor signaling.…”

Section: Discussioncontrasting

confidence: 51%

Changes in glucose tolerance and leptin responsiveness of rats offered a choice of lard, sucrose, and chow

Harris

Apolzan

2012

American Journal of Physiology-Regulatory, Integrative and Comp

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Harris RB, Apolzan JW. Changes in glucose tolerance and leptin responsiveness of rats offered a choice of lard, sucrose, and chow. Am J Physiol Regul Integr Comp Physiol 302: R1327-R1339, 2012. First published April 11, 2012 doi:10.1152/ajpregu.00477.2011.-Rats offered chow, lard, and 30% sucrose solution (choice) rapidly become obese. We tested metabolic disturbances in rats offered choice, chowϩlard, or chowϩ30% sucrose solution [chowϩliquid sucrose (LS)] and compared them with rats fed a composite 60% kcal fat, 7% sucrose diet [high-fat diet (HFD)], or a 10% kcal fat, 35% sucrose diet [low-fat diet (LFD)]. Choice rats had the highest energy intake, but HFD rats gained the most weight. After 23 days carcass fat was the same for choice, HFD, chowϩlard, and chowϩLS groups. Glucose clearance was the same for all groups during an intraperitoneal glucose tolerance test (GTT) on day 12, but fasting insulin was increased in choice, LFD fed, and chowϩLS rats. By contrast, only choice and chowϩLS rats were resistant to an intraperitoneal injection of 2 mg leptin/kg on day 17. In experiment 2 choice rats were insulin insensitive during an intraperitoneal GTT, but this was corrected in an oral GTT due to GLP-1 release. UCP-1 protein was increased in brown fat and inguinal white fat in choice rats, and this was associated with a significant increase in energy expenditure of choice rats during the dark period whether expenditure was expressed on a per animal or a metabolic body size basis. The increase in expenditure obviously was not great enough to prevent development of obesity. Further studies are required to determine the mechanistic basis of the rapid onset of leptin resistance in choice rats and how consumption of sucrose solution drives this process. dietary sucrose; leptin resistance; UCP-1; energy expenditure DIET-INDUCED OBESITY is a commonly used rodent model that may be induced in a variety of ways including offering the animals a composite high-fat diet (HFD) (18), a cafeteria diet (68), or sucrose or fructose solution in addition to dry food (5, 31). A recent review by Panchal and Brown (46) concludes that rats fed high-fat, high-carbohydrate diets provide the best rodent model of human metabolic syndrome due to the development of obesity, hyperinsulinemia, hyperlipidemia, hepatic steatosis, and cardiovascular abnormalities. Hepatic and skeletal muscle insulin resistance is evident within 4 wk (12, 63), but it may take months for additional aspects of the metabolic syndrome to develop in mice (42, 47) and rats (48). We and others have demonstrated that rats offered lard and sucrose solution in addition to chow (choice) overeat and rapidly gain body fat (3,36). This increase in adiposity has been associated with the development of glucose intolerance (35), disruption of central anorexigenic and orexigenic neuropeptide expression (36), and a suppression of the hypothalamic, pituitary, adrenal (HPA) axis response to stress (49). The adverse metabolic changes appear to occur more rapidly in choice rats than has...

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Section: Discussioncontrasting

confidence: 51%

Changes in glucose tolerance and leptin responsiveness of rats offered a choice of lard, sucrose, and chow

Harris

Apolzan

2012

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Previous reports have suggested that the obesity-prone OM and obesity-resistant S5B rats differ neurochemically, behaviorally, and physiologically in their response to consumption of dietary fat [1, 3, 4, 8, 29–39]. Several studies have impacted the focus of the current experiments and led to the investigation of differences in the GI tract of these rats.…”

Section: Discussionmentioning

confidence: 96%

CD36 mRNA in the Gastrointestinal Tract Is Differentially Regulated by Dietary Fat Intake in Obesity-Prone and Obesity-Resistant Rats

2012

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Background The gastrointestinal tract (GI) is important for detection and transport of consumed nutrients and has been implicated in susceptibility to diet-induced obesity in various rat strains. Aims The current studies investigated the regulation of CD36, a receptor which facilitates uptake of long-chain fatty acids, in the GI tract of obesity-prone Osborne–Mendel and obesity-resistant S5B rats fed a high-fat diet. Methods Osborne–Mendel and S5B rats consumed a high-fat diet (HFD, 55 % kcal from fat) or a low-fat diet (10 % kcal from fat) for either 3 or 14 days. CD36 messenger RNA (mRNA) levels were measured from circumvallate papillae of the tongue and from duodenal enterocytes. Results In Osborne–Mendel rats, consumption of HFD for 3 and 14 days led to an increase in CD36 mRNA on circumvallate papillae and in duodenal enterocytes. CD36 mRNA levels were positively correlated with body weight gain and kilocalories consumed at 3 days. In S5B rats, consumption of HFD for 3 days did not alter CD36 mRNA levels on circumvallate papillae or in the duodenum. Duodenal CD36 levels were elevated in S5B rats following 14 days of HFD consumption. CD36 mRNA levels in the duodenum were positively correlated with body weight gain and kilocalories consumed at 14 days. Conclusions These data support the differential sensing of nutrients by two regions of the GI tract of obesity-prone and obesity-resistant rats consuming HFD and suggest a role for CD36 in the strain-specific susceptibility to obesity.

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“…For example, in rats susceptible to obesity (Osborne-Mendel rats) the amplitude of rhythm of leptin and insulin was about 50% that in rats relatively resistant to obesity [45]. Other 24 h rhythms are affected by high-fat diet in animals.…”

Section: Discussionmentioning

confidence: 98%

Effect of a high-fat diet on 24-h pattern of circulating levels of prolactin, luteinizing hormone, testosterone, corticosterone, thyroid-stimulating hormone and glucose, and pineal melatonin content, in rats

Cano

Jiménez-Ortega

Larrad

et al. 2008

Endocr

107

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Circadian rhythmicity is affected in obese subjects. This article analyzes the effect of a high-fat diet (35% fat) on 24-h changes circulating prolactin, luteinizing hormone (LH), testosterone, corticosterone, thyroid-stimulating hormone (TSH) and glucose, and pineal melatonin content, in rats. When body weight of rats reached the values of morbid obesity, the animals were sacrificed at six different time intervals throughout a 24-h cycle, together with age-matched controls fed a normal diet (4% fat). Plasma hormone levels were measured by specific radioimmunoassays and glucose concentration by an automated glucose oxidase method. In rats under a high-fat diet, a significant disruption of the 24-h pattern of plasma TSH, LH, and testosterone and a slight disruption of prolactin rhythm were found. Additionally, high-fat fed rats showed significantly lower total values of plasma TSH and testosterone and absence of correlation between testosterone and circulating LH levels. Plasma corticosterone levels increased significantly in high-fat fed rats and their 24-h variation became blunted. In obese animals, a significant hyperglycemia developed, individual plasma glucose values correlating with circulating corticosterone in high-fat fed rats only. The amplitude of the nocturnal pineal melatonin peak decreased significantly in high-fat fed rats. The results underlie the significant effects that obesity has on circadian organization of hormone secretion.

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Effects of Diet and Time of the Day on Serum and CSF Leptin Levels in Osborne‐Mendel and S5B/Pl Rats

Cited by 20 publications

References 49 publications

Changes in glucose tolerance and leptin responsiveness of rats offered a choice of lard, sucrose, and chow

Changes in glucose tolerance and leptin responsiveness of rats offered a choice of lard, sucrose, and chow

CD36 mRNA in the Gastrointestinal Tract Is Differentially Regulated by Dietary Fat Intake in Obesity-Prone and Obesity-Resistant Rats

Effect of a high-fat diet on 24-h pattern of circulating levels of prolactin, luteinizing hormone, testosterone, corticosterone, thyroid-stimulating hormone and glucose, and pineal melatonin content, in rats

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