Disappearance of diurnal rhythm of energy expenditure in genetically diabetic obese rats

Ichikawa, Mineko; Miyasaka, Kyoko; Ohta, Motoko; Fujita, Yoshiji; Funakoshi, Akihiro

doi:10.1016/s0016-5085(98)83597-x

Cited by 4 publications

(15 citation statements)

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“…Because the SCN projects to the parovcellar region of the PVN [28,47], the SCN may impose a daily rhythm on physical activity and energy expenditure in part though the actions of neuromedin in the PVN. This is an especially intriguing possibility given the links between clock gene deficiencies and obesity [20,90], and given the decreased amplitude of the daily rhythm in energy expenditure seen in diabetic obese rats [32,66].…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of the hypothalamic paraventricular nucleus to the locomotor-activating effects of neuromedin U in obesity

2007

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Obesity is associated with a decrease in energy expenditure relative to energy intake. The decrease in physical activity associated with obesity in several species, including humans, contributes to decreased energy expenditure. Several hormones and neuropeptides that affect appetite also modulate physical activity, including neuromedin U (NMU), a peptide found in the gut and brain. We have demonstrated that NMU microinjected into the hypothalamic paraventricular nucleus (PVN) in rats increases the energy expenditure associated with physical activity, called non-exercise activity thermogenesis (NEAT). Here we examined whether obesity in rats is related to decreased sensitivity of the PVN to the locomotor-activating effect of NMU. Diet-induced obese (DIO) rats and lean, dietresistant (DR) rats were given PVN microinjections of increasing doses of NMU both before and after one month on a high-fat diet. We found that NMU increases physical activity, energy expenditure, and NEAT in a dose-dependent manner in both DR and DIO rats, both before and after one month on the high-fat diet. Before high-fat feeding, the obesity-prone and lean rats showed similar levels of physical activity after intra-PVN microinjections of NMU. After one month of the high-fat diet, however, the obesity-resistant rats showed significantly more NMU-induced physical activity compared to the obese DIO rats. Taken together with previous studies, these results suggest that obesity may represent a state associated with decreased central sensitivity to neuropeptides such as NMU that increase physical activity and therefore energy expenditure.

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Section: Discussionmentioning

confidence: 99%

Sensitivity of the hypothalamic paraventricular nucleus to the locomotor-activating effects of neuromedin U in obesity

2007

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“…The diurnal rhythm of energy expenditure associated with the highest and lowest values for energy consumption per hour was observed over dark and light periods, respectively, for both strains at 8 weeks of age (5,6). Two peaks, one between 05:00 and 08:00 and the other between 20:00 and 22:00, were observed.…”

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confidence: 83%

“…The metabolic study was conducted at 8 and 24 weeks of age because NIDDM manifests at 18 weeks of age in OLETF rats without any treatment (1) and the daily profile of energy expenditure at 8 weeks of age in OLETF rats was normal (5,6).…”

Section: Metabolic Study and Determinationsmentioning

confidence: 99%

“…Two peaks, one between 05:00 and 08:00 and the other between 20:00 and 22:00, were observed. However, these two peaks had disappeared in OLETF rats at 24 weeks of age after the manifestation of NIDDM, while these peaks were still substantial in normal control LETO rats at 24 weeks of age (5,6). The profile of energy expenditure in OLETF rats with NIDDM at 24 weeks of age was also different from that in streptozotocin-induced insulin-dependent diabetes mellitus (IDDM) LETO rats, which constituted one peak (6).…”

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confidence: 93%

“…We have previously examined the daily profile of energy expenditure in OLETF and control [Long Evans Tokushima (LETO)] rats at 8 and 24 weeks of age (5,6). The diurnal rhythm of energy expenditure associated with the highest and lowest values for energy consumption per hour was observed over dark and light periods, respectively, for both strains at 8 weeks of age (5,6).…”

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A Peroxisome Proliferator-Activated Receptor γ Agonist Influenced Daily Profile of Energy Expenditure in Genetically Obese Diabetic Rats

Yoshida

Ichikawa

Ohta

et al. 2002

Japanese Journal of Pharmacology

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ABSTRACT-Otsuka Long Evans Tokushima Fatty (OLETF) rats were developed as a model of noninsulin-dependent diabetes mellitus (NIDDM) with mild obesity. We reported that the daily profiles of energy expenditure associated with two peaks (one between 05:00 and 08:00 and the other between 20:00 and 22:00) were observed at 8 weeks of age (without NIDDM), while these two peaks disappeared at 24 weeks of age with NIDDM. As a new anti-diabetic drug, a peroxisome proliferator-activated receptor C agonist pioglitazone hydrochloride has been developed, we examined whether pioglitazone normalized daily profiles of energy expenditure at 24 weeks of age. A control diet and pioglitazone (0.1%)-containing diet were fed from 6 weeks of age. The two peaks of daily profiles of energy expenditure, which disappeared in OLETF rats with the control diet at 24 weeks of age, were reproduced by administration of pioglitazone. The respiratory quotient was lower and fat derived energy used for combustion was increased by pioglitazone at both ages. The body weight, daily food intake, plasma levels of fat, insulin, leptin and the wet weight of visceral fat were not influenced, but the levels of blood hemoglobin A1c and plasma tumor necrosis factor = were decreased by pioglitazone. Administration of pioglitazone improved daily profiles of energy expenditure via affecting glucose and fat metabolisms.Keywords: Energy expenditure, Non-insulin-dependent diabetes mellitus, Obesity, Peroxisome proliferator-activated receptor C Otsuka Long Evans Tokushima Fatty (OLETF) rats were developed as a model of non-insulin-dependent diabetes mellitus (NIDDM) with mild obesity (1). One mechanism of obesity in OLETF rats is disruption of the cholecystokinin (CCK)-A-receptor gene (2, 3). The CCK-A receptor has been implicated in satiety and a disrupted CCK-Areceptor gene induced hyperphagia (4). The characteristic features of OLETF rats are late onset of hyperglycemia at about 18 weeks of age, followed by insulin deficiency at about 65 weeks (1). In an original study by Kawano et al. 1992 (1), rats were divided to three groups after an oral glucose tolerance test (OGTT) was conducted. Glucose (2 g /kg) solution was given per os, and plasma levels of glucose were measured before and at 30, 60, 90 and 120 min: 1) Diabetic type rats had a peak level of plasma glucose >16.8 mM and a level of plasma glucose at 120 min >11.2 mM, and only rats that showed both conditions by OGTT were diagnosed with clinical DM; 2) if either of the two conditions was observed in the rats, they were diagnosed with impaired glucose tolerance (IGT); and 3) normal type, where neither DM nor IGT was present. After 23 weeks of age, OLETF rats with normal type parameters were not observed (94.7% with DM and 5.2% with IGT, respectively) (1).We have previously examined the daily profile of energy expenditure in OLETF and control [Long Evans Tokushima (LETO)] rats at 8 and 24 weeks of age (5, 6). The diurnal rhythm of energy expenditure associated with the highest and lowest values for energy co...

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Oral administration of interferon tau enhances oxidation of energy substrates and reduces adiposity in Zucker diabetic fatty rats

et al. 2013

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Male Zucker diabetic fatty (ZDF) rats were used to study effects of oral administration of interferon tau (IFNT) in reducing obesity. Eighteen ZDF rats (28 days of age) were assigned randomly to receive 0, 4 or 8 μg IFNT/kg body weight (BW) per day (n=6/group) for 8 weeks. Water consumption was measured every two days. Food intake and BW were recorded weekly. Energy expenditure in 4-, 6-, 8-, and 10-week-old rats was determined using indirect calorimetry. Starting at 7 weeks of age, urinary glucose and ketone bodies were tested daily. Rates of glucose and oleate oxidation in liver, brown adipose tissue, and abdominal adipose tissue, leucine catabolism in skeletal muscle, and lipolysis in white and brown adipose tissues were greater for rats treated with 8 μg IFNT/kg BW/day in comparison with control rats. Treatment with 8 μg IFNT/kg BW/day increased heat production, reduced BW gain and adiposity, ameliorated fatty liver syndrome, delayed the onset of diabetes, and decreased concentrations of glucose, free fatty acids, triacylglycerol, cholesterol, and branched-chain amino acids in plasma, compared to control rats. Oral administration of 8 μg IFNT/kg BW/day ameliorated oxidative stress in skeletal muscle, liver and adipose tissue, as indicated by decreased ratios of oxidized glutathione to reduced glutathione and increased concentrations of the antioxidant tetrahydrobiopterin. These results indicate that IFNT stimulates oxidation of energy substrates and reduces obesity in ZDF rats and may have broad important implications for preventing and treating obesity-related diseases in mammals.

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Disappearance of diurnal rhythm of energy expenditure in genetically diabetic obese rats

Cited by 4 publications

References 0 publications

Sensitivity of the hypothalamic paraventricular nucleus to the locomotor-activating effects of neuromedin U in obesity

Sensitivity of the hypothalamic paraventricular nucleus to the locomotor-activating effects of neuromedin U in obesity

A Peroxisome Proliferator-Activated Receptor γ Agonist Influenced Daily Profile of Energy Expenditure in Genetically Obese Diabetic Rats

Oral administration of interferon tau enhances oxidation of energy substrates and reduces adiposity in Zucker diabetic fatty rats

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