Exercise training improves insulin sensitivity in the obese Zucker rat

Walberg, Janet L.; Upton, David E.; Stern, Judith S.

doi:10.1016/0026-0495(84)90090-8

Cited by 9 publications

(7 citation statements)

References 18 publications

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“…female obese rats with swim training (70,71), several other groups have reported results that are similar to our study (36,41,61). Nevertheless, even in studies that reported reductions in weight gain, exercise only delayed but did not prevent the development of obesity (70).…”

Section: Discussionsupporting

confidence: 87%

“…Although some studies have reported that insulin resistance in this model is refractory to exercise (41), others have reported improvements (36,71). Furthermore, even in studies reporting an improvement in insulin sensitivity, there were no reductions in fasting plasma insulin concentrations (18,36,71). While our study involved 8 wk of exercise at 10 m/min, Xiang et al (74) exercised the rats for 4-5 wk at 24 m/min.…”

Section: Discussionmentioning

confidence: 63%

“…However, a number of other studies have reported no reductions in plasma insulin levels with exercise in obese rats (11,14,19,33,35,63) as well as humans (64). Although some studies have reported that insulin resistance in this model is refractory to exercise (41), others have reported improvements (36,71). Furthermore, even in studies reporting an improvement in insulin sensitivity, there were no reductions in fasting plasma insulin concentrations (18,36,71).…”

Section: Discussionmentioning

confidence: 96%

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Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D₁receptor dysfunction in obese rats

Muhammad

Lokhandwala

Banday

2011

American Journal of Physiology-Renal Physiology

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 96%

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Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D₁receptor dysfunction in obese rats

Muhammad

Lokhandwala

Banday

2011

American Journal of Physiology-Renal Physiology

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“…These observations are confirmed in animal studies. In obese Zucker (fa/fa) rats characterized by moderate hypertension (3,4), hyperlipidemia (5,6), and insulin resistance/impaired glucose tolerance (7,8), exercise improves insulin sensitivity (9) and reduces blood lipids (10), blood pressure (4), and obesity (11,12).…”

mentioning

confidence: 99%

Long-Term AICAR Administration Reduces Metabolic Disturbances and Lowers Blood Pressure in Rats Displaying Features of the Insulin Resistance Syndrome

et al. 2002

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The insulin resistance syndrome is characterized by several risk factors for cardiovascular disease. Chronic chemical activation of AMP-activated protein kinase by the adenosine analog 5-aminoimidazole-4-carboxamide-1-␤-D-ribofuranoside (AICAR) has been shown to augment insulin action, upregulate mitochondrial enzymes in skeletal muscles, and decrease the content of intraabdominal fat. Furthermore, acute AICAR exposure has been found to reduce sterol and fatty acid synthesis in rat hepatocytes incubated in vitro as well as suppress endogenous glucose production in rats under euglycemic clamp conditions. To investigate whether chronic AICAR administration, in addition to the beneficial effects on insulin sensitivity, is capable of improving other phenotypes associated with the insulin resistance syndrome, obese Zucker (fa/fa) rats (n ‫؍‬ 6) exhibiting insulin resistance, hyperlipidemia, and hypertension were subcutaneously injected with AICAR (0.5 mg/g body wt) daily for 7 weeks. Obese control rats were either pair-fed (PF) (n ‫؍‬ 6) or ad libitum-fed (AL) (n ‫؍‬ 6). Lean Zucker rats (fa/؊) (n ‫؍‬ 8) served as a reference group. AICAR administration significantly reduced plasma triglyceride levels (P < 0.01 for AICAR vs. AL, and P ‫؍‬ 0.05 for AICAR vs. PF) and free fatty acids (P < 0.01 for AICAR vs. AL, and P < 0.05 for AICAR vs. PF) and increased HDL cholesterol levels (P < 0.01 for AICAR vs. AL and PF). AICAR treatment also lowered systolic blood pressure by 14.6 ؎ 4.3 mmHg (P < 0.05), and AICAR-treated animals exhibited a tendency toward decreased intra-abdominal fat content. Furthermore, AICAR administration normalized the oral glucose tolerance test and decreased fasting concentrations of glucose and insulin close to the level of the lean animals. Finally, in line with previous findings, AICAR treatment was also found to enhance GLUT4 protein expression and to increase maximally insulin-stimulated glucose transport in primarily white fast-twitch muscles. Our data provide strong evidence that longterm administration of AICAR improves glucose tolerance, improves the lipid profile, and reduces systolic blood pressure in an insulin-resistant animal model. The present study gives additional support to the hypothesis that AMPK activation might be a potential future pharmacological strategy for treating the insulin resistance syndrome.

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“…Furthermore, week old obese female Zucker rats had above-normal body protein content (Walberg et al 1984). Obese female Zucker rats deposited protein at rates similar to those of lean rats even when dietary protein content was below optimum levels (Radcliffe and Webster 1979).…”

mentioning

confidence: 95%

Growth and protein metabolism in exercised, estrogen-fed and developing female Zucker rats

VandeVoort

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Statement of Rationale Experiment 1: Effects of exercise on growth and 3-methyIhistidine excretion of female Zucker rats Experiment 2: Effects of ethynyl estradiol on body composition growth and muscle protein catabolism of female Zucker rats Experiment 3: Development and protein metabolism of female Zucker rats 4 REVIEW OF LITERATURE The Zucker Rat as a Model of Obesity Relationship of hyperphagia and body protein content to the obesity of the Zucker rat 7 Evidence for Subnormal Estrogen Status of Female Zucker Rats ... 10 Protein Turnover in Rats 12 Protein synthesis 13 Regulation of protein synthesis 13 Measurement of protein synthesis 14 Protein degradation and 3-methylhistidine excretion 15 Urinary 3-MH as an indicator of skeletal muscle catabolism. . 16 Protein Metabolism in the Zucker Rat 17 Exercise Studies in Rats 19 Food intake and body composition of treadmill exercised rats 20 Effects of exercise on protein turnover in rats 21 Effects of exercise on food intake and body composition of Zucker rats 23 Interrelationship of Protein Metabolism, Corticosterone and Obesity in the Zucker Rat 25 Effects of corticosterone in normal rats 25 Relationships of corticosterone to the obesity of the Zucker rat 27 Effect of adrenalectomy on the obese Zucker rat 28 EXPERIMENT 1: EFFECTS OF EXERCISE ON GROWTH AND 3-METHYLHISTIDINE EXCRETION OF FEMALE ZUCKER RATS Introduction iii Methods Results Weight gain and food intake Body composition and organ weights Urinary 3-methylhistidine Discussion Weight gain and food intake Body composition and organ weights Urinary 3-methylhistidine EXPERIMENT 2: EFFECTS OF ETHYNYL ESTRADIOL ON BODY COMPOSITION, GROWTH AND 3-METHYLHISTIDINE EXCRETION OF FEMALE ZUCKER RATS .... Introduction 49 Methods 50 Results 52 Body weight and weight gain 52 Body composition and organ weights 52 Urinary 3-methylhistidine excretion 54 Discussion 54 Body weight and weight gain 54 Body composition and organ weights 58 Urinary 3-methylhistidine 69 EXPERIMENT 3: DEVELOPMENT AND PROTEIN METABOLISM OF FEMALE ZUCKER RATS 71 Discussion 76 Body composition 76 Incorporation of ^H-phenylalanine 84 Urinary 3-methylhistidine excretion 86 GENERAL DISCUSSION 89

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Exercise training improves insulin sensitivity in the obese Zucker rat

Cited by 9 publications

References 18 publications

Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D₁receptor dysfunction in obese rats

Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D₁receptor dysfunction in obese rats

Long-Term AICAR Administration Reduces Metabolic Disturbances and Lowers Blood Pressure in Rats Displaying Features of the Insulin Resistance Syndrome

Growth and protein metabolism in exercised, estrogen-fed and developing female Zucker rats

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Exercise training improves insulin sensitivity in the obese Zucker rat

Cited by 9 publications

References 18 publications

Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D1receptor dysfunction in obese rats

Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D1receptor dysfunction in obese rats

Long-Term AICAR Administration Reduces Metabolic Disturbances and Lowers Blood Pressure in Rats Displaying Features of the Insulin Resistance Syndrome

Growth and protein metabolism in exercised, estrogen-fed and developing female Zucker rats

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Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D₁receptor dysfunction in obese rats

Exercise reduces oxidative stress but does not alleviate hyperinsulinemia or renal dopamine D₁receptor dysfunction in obese rats