Metabolic features of rats resistant to a high-fat diet.

We assessed the metabolic characteristics of high-fat-diet-resistant (DR) rats. Body weight, energy intake, locomotor activity, oxygen consumption, plasma leptin and lipid levels, size of visceral-fat adipocytes, and mRNA levels of genes related to lipid metabolism were measured in control rats fed standard chow and in obesity-prone (high-fat-diet-induced obesity, DIO) and DR rats fed a high-fat diet. Glucose tolerance and insulin tolerance tests were also performed. DIO rats gained weight more rapidly than did DR and control rats; DR rats gained less weight than did DIO rats despite similar energy intake. Energy expenditure did not differ among the three groups. The diameter of visceral-fat adipocytes was similar in DR and control rats. mRNA levels of genes involved in lipogenesis, such as fatty acid synthase and acetyl-CoA carboxylase, tended to be lower in DR than in control and DIO rats, whereas those of carnitine palmitoyltransferase 1a, which is involved in fatty acid β-oxidation, were greater in DR rats than in the other groups. DIO rats showed hyperinsulinemia and glucose intolerance, whereas DR rats had high sensitivity to insulin. DR rats show suppression of lipogenesis and acceleration of fatty acid β-oxidation in the visceral fat. These characteristics likely contribute to the anti-obesity phenotype of DR rats.

Akieda-Asai S ，Koda S ，Sugiyama M ，Hasegawa K ，Furuya M ，Miyazato M ，Date Y ... -  《Obesity Research & Clinical Practice》

High dietary protein decreases fat deposition induced by high-fat and high-sucrose diet in rats.

Chaumontet C ，Even PC ，Schwarz J ，Simonin-Foucault A ，Piedcoq J ，Fromentin G ，Azzout-Marniche D ，Tomé D ... -  《-》

Antiobesity activities of indole-3-carbinol in high-fat-diet-induced obese mice.

This study investigated the effects of indole-3-carbinol (I3C), a cruciferous vegetable derivative, on obesity and its associated factors in high-fat-diet-induced obese (DIO) mice. Eighteen male C57BL/6 mice were randomly assigned to one of three groups: basal, high fat (HF), and HF + 5 mg/kg of I3C intraperitoneally (HFI). After 12 wk of treatment, obesity-associated factors, including body weight, organ weight, serum concentrations of glucose, triacylglycerol, insulin, and adipokines, and macrophage accumulation and lipid metabolism-associated factors in epididymal adipose tissue were measured. Body weight and epididymal adipose tissue weight were greater (P < 0.01), and adipocytes were larger in the HF group than in the basal and HFI groups. Compared with the HF group, the HFI group had improved glucose tolerance, a higher serum adiponectin concentration, lower serum glucose, triacylglycerol, insulin, and leptin concentrations, and less F4/80 expression in epididymal adipose tissue (P < 0.001). Furthermore, I3C treatment decreased acetyl coenzyme A carboxylase mRNA expression (P < 0.05) and increased peroxisome proliferator-activated receptor-γ protein expression (P < 0.05) in epididymal adipose tissue of DIO mice. The I3C treatment decreased body weight and fat accumulation and infiltrated macrophages in epididymal adipose tissue of DIO mice, and these reductions were associated with improved glucose tolerance and with modulated expression of adipokines and lipogenic-associated gene products, including acetyl coenzyme A carboxylase and peroxisome proliferator-activated receptor-γ.

Chang HP ，Wang ML ，Chan MH ，Chiu YS ，Chen YH ... -  《-》

Enzymatically synthesized glycogen reduces lipid accumulation in diet-induced obese rats.

Based on a recent study indicating that enzymatically synthesized glycogen (ESG) possesses a dietary, fiber-like action, we hypothesized that ESG can reduce the risk of obesity. In this study, the antiobesity effects of ESG were investigated in a model of diet-induced obesity. Male Sprague-Dawley rats were divided into 4 groups and fed a normal or high-fat diet, with or without 20% ESG, for 4 weeks. Body weight, food intake, lipid deposition in the white adipose tissues and liver, fecal lipid excretion, and plasma lipid profiles were measured. At week 3, the body fat mass was measured using an x-ray computed tomography system, which showed that ESG significantly suppressed the high-fat diet-induced lipid accumulation. Similar results were observed in the weight of the adipose tissue after the experiment. Moreover, ESG significantly suppressed the lipid accumulation in the liver but increased fecal lipid excretion. The plasma concentrations of triacylglycerol and nonesterified fatty acid were lowered after a high-fat diet, whereas the total bile acid concentration was increased by ESG. However, the hepatic messenger RNA (mRNA) levels of enzymes related to lipid metabolism were not affected by ESG. Conversely, the mRNA levels of long-chain acyl-CoA dehydrogenase and medium-chain acyl-CoA dehydrogenase were up-regulated by ESG in the muscle. These results suggest that the combined effects of increased fecal lipid excretion, increased mRNA levels of enzymes that oxidize fatty acids in the muscle, and increased total bile acid concentration in the plasma mediate the inhibitory effect of ESG on lipid accumulation.

Furuyashiki T ，Ogawa R ，Nakayama Y ，Honda K ，Kamisoyama H ，Takata H ，Yasuda M ，Kuriki T ，Ashida H ... -  《-》

Postweaning low-calcium diet promotes later-life obesity induced by a high-fat diet.

The aim of this study was to investigate the effects of a postweaning low-calcium diet on later obesity and explore the underlying mechanisms. Ninety-six male rats were weaned at 3 weeks of age, fed standard (STD: 0.50% calcium, n=48) and low-calcium (LC: 0.15% calcium, n=48) diets for 3 weeks, and then fed the standard diet for a 3-week washout period successively. Finally, the STD rats were divided into STD control and high-fat diet (HFD) groups, and the LC ones into LC control and LC+HFD (LCHF) groups. The STD and LC rats were fed the standard diet, while the HFD control and LCFD ones were fed a high-fat diet for 6 weeks to induce obesity. During the three feeding periods, adenosine-monophosphate-activated protein kinase (AMPK) and its responsive proteins phospho-acetyl-coA carboxylase, carnitine palmitoyltransferase 1 and uncoupling protein 3 were persistently down-regulated in the LC group (decreased by 18%, 24%, 18% and 20%, respectively) versus the STD group, and these effects were significantly more pronounced in the LCHFD group (decreased by 21%, 30%, 23% and 25%, respectively) than the HFD group by a later high-fat stimuli, causing more fat and body weight in adulthood. However, lipolysis enzymes, serum leptin, insulin and lipids were not significantly affected until the body weight and fat content changed at 15 weeks of age. The results suggest that the low-calcium diet after weaning promotes rat adult-onset obesity induced by high-fat diet, which might be achieved by programming expressions of genes involved in AMPK pathway.

He YH ，Li ST ，Wang YY ，Wang G ，He Y ，Liao XL ，Sun CH ，Li Y ... -  《-》