Voluntary physical activity and leucine correct impairments in muscle protein synthesis in partially pancreatectomised rats

Serino, A. S.; Adegoke, Olasunkanmi A. J.; Zargar, Sana; Gordon, Carly S.; Szigiato, Andrei-Alexandru; Hawke, Thomas J.; Riddell, Michael C.

doi:10.1007/s00125-011-2296-0

Cited by 2 publications

(2 citation statements)

References 43 publications

(75 reference statements)

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“…This amount is equivalent to 0.48 g leucine/kg, and represents ~40% of a rat's daily leucine consumption (Serino et al. ). Rats were sacrificed at different times (0.5–2 h) after gavage and soleus muscle dissected.…”

Section: Methodsmentioning

confidence: 99%

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Amino acid-induced impairment of insulin sensitivity in healthy and obese rats is reversible

et al. 2014

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High‐protein diets (HPDs) promote weight loss but other studies implicate these diets and their constituent amino acids (AAs) in insulin resistance. We hypothesized that AA‐induced insulin resistance is a temporal and reversible metabolic event. L6 myotubes were serum deprived for 4 h and then incubated in AA and/or insulin (100 nmol/L). Another group of cells was incubated overnight in AA + insulin, starved again, and then reincubated with AA and insulin. Mammalian (mechanistic) target of rapamycin complex 1 (mTORC1) signaling and glucose uptake were then measured. Healthy or insulin‐resistant rats were gavaged with leucine (0.48 g/kg) and insulin sensitivity was examined. In myotubes, incubation with AA and insulin significantly (P <0.05) increased the phosphorylation of the mTORC1 substrate ribosomal protein S6 kinase 1 (S6K1, T389) and of insulin receptor substrate 1 (IRS‐1, serine residues), but suppressed insulin‐stimulated glucose uptake by 40% (P <0.01). These modifications were mTORC1‐dependent and were reversible. In vivo, leucine gavage reversibly increased S6K1 phosphorylation and IRS‐1 serine phosphorylation 5‐ to 12‐fold in skeletal muscle and impaired insulin tolerance of glucose (P <0.05) in lean rats. In insulin‐resistant rats, the impairment of whole blood glucose and AA metabolism induced by leucine gavage (0.001 < P <0.05) was more severe than that observed in lean rats; however, the impairment was reversible within 24 h of treatment. If these data are confirmed in long‐term studies, it would imply that the use of leucine/HPD in treating metabolic diseases is unlikely to have lasting negative effects on insulin sensitivity.

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Section: Methodsmentioning

confidence: 99%

“…The second group was gavaged with leucine (1 g/ 50 mL ddH 2 O, 2.4 mL/100 g body weight). This amount is equivalent to 0.48 g leucine/kg, and represents~40% of a rat's daily leucine consumption (Serino et al 2011).…”

Section: Rat Studiesmentioning

confidence: 99%

Amino acid-induced impairment of insulin sensitivity in healthy and obese rats is reversible

et al. 2014

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Exercise and Type 1 Diabetes (T1DM)

Galassetti

Riddell

2013

Comprehensive Physiology

113

118

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Physical exercise is firmly incorporated in the management of type 1 diabetes (T1DM), due to multiple recognized beneficial health effects (cardiovascular disease prevention being preeminent). When glycemic values are not excessively low or high at the time of exercise, few absolute contraindications exist; practical guidelines regarding amount, type, and duration of age-appropriate exercise are regularly updated by entities such as the American Diabetes Association and the International Society for Pediatric and Adolescent Diabetes. Practical implementation of exercise regimens, however, may at times be problematic. In the poorly controlled patient, specific structural changes may occur within skeletal muscle fiber, which is considered by some to be a disease-specific myopathy. Further, even in well-controlled patients, several homeostatic mechanisms regulating carbohydrate metabolism often become impaired, causing hypo- or hyperglycemia during and/or after exercise. Some altered responses may be related to inappropriate exogenous insulin administration, but are often also partly caused by the "metabolic memory" of prior glycemic events. In this context, prior hyperglycemia correlates with increased inflammatory and oxidative stress responses, possibly modulating key exercise-associated cardio-protective pathways. Similarly, prior hypoglycemia correlates with impaired glucose counterregulation, resulting in greater likelihood of further hypoglycemia to develop. Additional exercise responses that may be altered in T1DM include growth factor release, which may be especially important in children and adolescents. These multiple alterations in the exercise response should not discourage physical activity in patients with T1DM, but rather should stimulate the quest for the identification of the exercise formats that maximize beneficial health effects.

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Voluntary physical activity and leucine correct impairments in muscle protein synthesis in partially pancreatectomised rats

Cited by 2 publications

References 43 publications

Amino acid-induced impairment of insulin sensitivity in healthy and obese rats is reversible

Amino acid-induced impairment of insulin sensitivity in healthy and obese rats is reversible

Exercise and Type 1 Diabetes (T1DM)

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