Calorie restriction initiated at middle age improved glucose tolerance without affecting age-related impairments of insulin signaling in rat skeletal muscle

Park, Seong Joon; Komatsu, Toshimitsu; Hayashi, Hiroko; Yamaza, Haruyoshi; Chiba, Takuya; Higami, Yoshikazu; Kuramoto, Kazunao; Shimokawa, Isao

doi:10.1016/j.exger.2006.06.055

Cited by 18 publications

(27 citation statements)

References 37 publications

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“…The basal level of pAkt in the 7-month CR group was significantly higher than that of the 7-month AL group but was similar to the glucose-stimulated levels in the AL group. The basal level of p-Akt was significantly reduced in the (Park et al 2006) 22-month CR group as compared with the 7-month CR group but levels tended to increase (P=0.0987) in the 22-month CR group after glucose injection. Glucose injection also resulted in a significant increase in p-PKCζ/λ levels in the 7-month AL group (Fig.…”

Section: Effect Of Cr On P-ir Levels In Adipose Tissuementioning

confidence: 89%

“…4a). There was an age-related decrease in serum adiponectin concen- (Park et al 2006) trations in the AL group, but not in the CR group. CR resulted in a significant increase in serum adiponectin.…”

Section: Effect Of Cr On Plasma Adiponectin and P-ampkαmentioning

confidence: 90%

“…The results of GTT for the present animals are published elsewhere (Park et al 2006). Briefly, blood glucose concentrations increased to a peak at 15 min after ip glucose injection and gradually decreased thereafter.…”

Section: Effect Of Cr On Body Weight and Epididymal Fat Pad Weightmentioning

confidence: 96%

“…CR in middle-aged rats, however, had no significant effect on the age-related impairments of insulin signaling in response to glucose, whereas glucose intolerance was improved. These findings indicate two possibilities: firstly, the presence of an insulin-independent mechanism in skeletal muscle for glucose metabolism, and, secondly, the involvement of non-muscle tissues in glucose disposal (Park et al 2006).…”

mentioning

confidence: 89%

“…The adiponectin-AMPK pathway was also analyzed, because this pathway is involved in an insulin-independent mechanism for glucose metabolism. As noted in our previous paper (Park et al 2006), the effect of CR initiated in middle age is also important, because many clinical programs that aim to reduce calorie intake, and thus decrease body fat, are provided to prediabetic obese patients. Therefore, in the present study, we compared the effects of CR initiated in young or middle-aged rats.…”

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confidence: 99%

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Calorie restriction initiated at a young age activates the Akt/PKCζ/λ-Glut4 pathway in rat white adipose tissue in an insulin-independent manner

Park

Komatsu

Hayashi

et al. 2008

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Calorie restriction (CR) may exert an antiaging effect through a metabolic adaptation to limited energy intake. The present study investigated the effect of CR on insulin signaling in response to glucose load in the epididymal adipose tissue of male F344 rats at 7 and 22 months of age. Young and middle-aged rats were fed ad libitum (AL) or 30% CR diets for 4 months, underwent glucose tolerance tests and were sacrificed 15 min after an intraperitoneal glucose or saline injection to evaluate glucose-stimulated insulin response and subsequent activation of insulin signaling molecules in the adipose tissue. In the 7-and 22-month AL groups, glucose administration increased serum insulin levels and also increased phosphorylated (p) levels of the insulin receptor (IR), v-akt murine thymoma viral oncogene homolog (Akt), protein kinase C (PKC) ζ/λ and the membrane fraction of glucose transporter 4 (mGlut4). In contrast, in the 7-month CR group, p-Akt, p-PKCζ/λ and mGlut4 levels were upregulated without glucose stimulation; the glucose load augmented the p-IR level but there was no additional activation of the downstream molecules. In the 22-month CR group, these unexpected findings were not observed. In summary, basal levels of insulin signaling molecules such as p-Akt, p-PKCζ/λ, and mGlut4 were significantly increased with a low insulin response in the 7-month CR group. The present results suggest the presence of an age-specific insulin-independent mechanism that is induced by CR to regulate energy metabolism in white adipose tissue.

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Section: Effect Of Cr On P-ir Levels In Adipose Tissuementioning

confidence: 89%

Section: Effect Of Cr On Plasma Adiponectin and P-ampkαmentioning

confidence: 90%

Section: Effect Of Cr On Body Weight and Epididymal Fat Pad Weightmentioning

confidence: 96%

mentioning

confidence: 89%

mentioning

confidence: 99%

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Calorie restriction initiated at a young age activates the Akt/PKCζ/λ-Glut4 pathway in rat white adipose tissue in an insulin-independent manner

Park

Komatsu

Hayashi

et al. 2008

AGE

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The effect of different levels of dietary restriction on glucose homeostasis and metabolic memory

et al. 2018

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Over the past 50 years, dietary restriction (DR) has been shown to extend the life span of a wide variety of organisms. A hallmark feature of DR is improved glucose homeostasis resulting in increased glucose tolerance and insulin sensitivity of animals ranging from rodents to humans. In this study, we demonstrate the early effects of varying levels of DR on glucose tolerance. Within 10 days of 40% DR, glucose tolerance was significantly improved and by 120 days; 10 and 20% DR also showed enhanced glucose tolerance. All three levels of DR showed reduced adiposity, increased expression of genes involved in fat turnover, and a reduction in the expression for markers of inflammation. Studies have shown that mice fed a DR diet retained metabolic memory in terms of improved glucose tolerance even after DR is discontinued. We show that 40% DR not only has an early effect on glucose tolerance but also maintained it after DR was discontinued for 2 months. Therefore, improvement in glucose tolerance is brought about by all three levels of DR but the metabolic memory is not dose responsive.

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Dietary restriction improves systemic and muscular oxidative stress in type 2 diabetic Goto–Kakizaki rats

et al. 2011

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Type 2 diabetes is a heterogeneous metabolic disease characterized by insulin resistance and β-cell dysfunction leading to hyperglycaemia and dyslipidaemia. Dietary intervention seems to improve some of these cellular complications, namely insulin resistance. Our aim was to evaluate the effects of dietary restriction on systemic and skeletal muscle oxidative stress and insulin resistance in normal Wistar rats and Goto-Kakizaki (GK) rats, a non-obese type 2 diabetic animal model. Four-month-old normal and diabetic rats were separated in four groups. One group of each strain was maintained with ad libitum standard diet, and the other group was submitted to a dietary restriction (50% of control animals daily food intake), during 2 months. Metabolic profile, insulin resistance indexes and muscle lipids were determined. Oxidative stress parameters were also measured at systemic and muscle levels: protein carbonyl, 8-hydroxy-2'-deoxyguanosine and free 8-isoprostane. Dietary restriction improved lipid profile in both strains and urinary free 8-isoprostane and plasma carbonyl compounds in diabetic rats. An improvement of muscle triglycerides accumulation and 8-isoprostane concentration and a reduction of insulin resistance were also observed in GK rats. Our data show that dietary restriction ameliorates systemic and skeletal muscle oxidative stress state in type 2 diabetes, which is associated with improved insulin resistance.

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Calorie restriction initiated at middle age improved glucose tolerance without affecting age-related impairments of insulin signaling in rat skeletal muscle

Cited by 18 publications

References 37 publications

Calorie restriction initiated at a young age activates the Akt/PKCζ/λ-Glut4 pathway in rat white adipose tissue in an insulin-independent manner

Calorie restriction initiated at a young age activates the Akt/PKCζ/λ-Glut4 pathway in rat white adipose tissue in an insulin-independent manner

The effect of different levels of dietary restriction on glucose homeostasis and metabolic memory

Dietary restriction improves systemic and muscular oxidative stress in type 2 diabetic Goto–Kakizaki rats

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