Mechanism of enhanced insulin sensitivity in athletes. Increased blood flow, muscle glucose transport protein (GLUT-4) concentration, and glycogen synthase activity.

Ebeling, Pertti; Bourey, Raymond E.; Korányi, László; Tuominen, J. A.; Groop, L.; Henriksson, Jan; Mueckler, Mike; Sovijärvi, Anssi; Koivisto, Veikko A.

doi:10.1172/jci116747

Cited by 219 publications

(177 citation statements)

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“…After an overnight fast, a 4 h euglycaemic (5 mmol/l) hyperinsulinaemic clamp was performed by infusing short-acting insulin (Actrapid; Novo Nordisk, Denmark, 1.5 mU or 9 pmol ⋅ kg --1 ⋅ min --1 ) as previously described [13,14]. Indirect calorimetry was performed before and at the end of the insulin infusion for the determination of glucose and lipid oxidation [15].…”

Section: Subjects Design and Methodsmentioning

confidence: 99%

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Intramuscular triglyceride content is increased in IDDM

et al. 1998

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Increased lipid oxidation is related to insulin resistance [1]. Most of the fatty acids taken up by resting muscle are not oxidized directly, but enter an intramuscular pool with a slow turnover at rest and are the immediate source of lipid substrate for oxidation [2]. The NEFA taken up by muscle are incorporated to lipid droplets in muscle and 70--90 % of fatty acids entering the muscle are rapidly esterified to triglyceride (TG) [3]. For example, raising extracellular palmitate increases esterification, but does not increase intramuscular concentration of palmitate [4]. Part of the enhanced lipid oxidation can be derived from intramuscular sources [5].As compared to healthy subjects a sixfold increase of muscle (m) TG in patients with non-insulin-dependent diabetes mellitus [6], and a sevenfold increase in TG content in striated muscle in coronary bypass-operated patients with impaired glucose tolerance [7] have been reported in comparison to control groups. These patient groups are also characterized by insulin resistance. Sustained euglycaemic hyperinsulinaemia Diabetologia (1998) Summary Increased lipid oxidation is related to insulin resistance. Some of the enhanced lipid utilization may be derived from intramuscular sources. We studied muscle triglyceride (mTG) concentration and its relationship to insulin sensitivity in 10 healthy men (age 29 ± 2 years, BMI 23.3 ± 0.6 kg/m 2 ) and 17 men with insulin-dependent diabetes mellitus (IDDM) (age 30 ± 2 years, BMI 22.8 ± 0.5 kg/m 2 , diabetes duration 14 ± 2 years, HbA 1 c 7.7 ± 0.3 %, insulin dose 48 ± 3 U/day). Insulin sensitivity was measured with a 4 h euglycaemic (5 mmol/l) hyperinsulinaemic (1.5 mU or 9 pmol ⋅ kg --1 ⋅ min --1 ) clamp accompanied by indirect calorimetry before and at the end of the insulin infusion. A percutaneous biopsy was performed from m. vastus lateralis for the determination of mTG. At baseline the IDDM patients had higher glucose (10.2 ± 0.9 vs 5.6 ± 0.1 mmol/l, p < 0.001), insulin (40.3 ± 3.2 vs 23.2 ± 4.2 pmol/l, p < 0.01), HDL cholesterol (1.28 ± 0.06 vs 1.04 ± 0.03 mmol/l, p < 0.01) and mTG (32.9 ± 4.6 vs 13.6 ± 2.7 mmol/kg dry weight, p < 0.01) concentrations than the healthy men, respectively. The IDDM patients had lower insulin stimulated whole body total (--25 %, p < 0.001), oxidative (--18 %, p < 0.01) and non-oxidative glucose disposal rates (--43 %, p < 0.001), whereas lipid oxidation rate was higher in the basal state ( + 44 %, p < 0.01) and during hyperinsulinaemia ( + 283 %, p < 0.05). mTG concentrations did not change significantly during the clamp or correlate with insulin stimulated glucose disposal. In healthy men mTG correlated positively with lipid oxidation rate at the end of hyperinsulinaemia (r = 0.75, p < 0.05). In conclusion: 1) IDDM is associated with increased intramuscular TG content. 2) mTG content does not correlate with insulin sensitivity in healthy subjects or patients with IDDM. [Diabetologia (1998) 41: 111--115]

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Section: Subjects Design and Methodsmentioning

confidence: 99%

“…Appropriate tripalmitin standards were treated in the same manner as the muscle samples. Maximal aerobic power (VO 2 max) was determined using a work-conducted upright exercise test [14]. The estimation of body fat was calculated by summing up six skinfolds [24].…”

Section: Subjects Design and Methodsmentioning

confidence: 99%

Intramuscular triglyceride content is increased in IDDM

et al. 1998

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“…The mechanisms related to this improvement in glucose metabolism include the following: increased insulin sensitivity; upregulated GLUT4 translocation to the muscle cell membrane independently of the insulin pathway (Ebeling et al 1993); enhanced available glucose storage capacity, thereby facilitating the clearance of glucose from the circulation; reduced levels of visceral fat (Ibañez et al 2005), which is the primary cause of insulin resistance; and increased muscle mass, which is the primary tissue involved in glucose metabolism (Ebeling et al 1993).…”

Section: The Effects Of Exercise Interventions On Glycemic Control Inmentioning

confidence: 99%

Exercise interventions in polypathological aging patients that coexist with diabetes mellitus: improving functional status and quality of life

Cadore

Izquierdo

2015

AGE

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In elderly populations, diabetes is associated with reduced muscle strength, poor muscle quality, and accelerated loss of muscle mass. In addition, diabetes mellitus increases risk for accelerated aging and for the development of frailty syndrome. This disease is also associated with a polypathological condition, and its complications progressively affect quality of life and survival. Exercise interventions, including resistance training, represent the cornerstones of diabetes management, especially in patients at severe functional decline. This review manuscript aimed to describe the beneficial effects of different exercise interventions on the functional capacity of elderly diabetics, including those at polypathological condition. The SciELO, Science Citation Index, MEDLINE, Scopus, SPORTDiscus, and ScienceDirect databases were searched from 1980 to 2015 for articles published from original scientific investigations. In addition to the beneficial effects of exercise interventions on glycemic control, and on the cardiovascular risk factors associated with diabetes, physical exercise is an effective intervention to improve muscle strength, power output, and aerobic power and functional capacity in elderly diabetic patients. Thus, a combination of resistance and endurance training is the most effective exercise intervention to promote overall physical fitness in these patients. In addition, in diabetic patients with frailty and severe functional decline, a multicomponent exercise program including strength and power training, balance exercises, and gait retraining may be an effective intervention to reduce falls and improve functional capacity and quality of life in these patients.

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“…However, data from human muscle exercise studies have indicated that IL-6 produced by skeletal muscles might improve insulin sensitivity rather than induce insulin resistance (Helge et al, 2003). Exercise is known to induce glucose uptake in skeletal muscle (Ebeling et al, 1993;Kristiansen et al, 2000). Furthermore, in response to exercise the release of IL-6 from working muscles is enhanced (Steensberg et al, 2000).…”

Section: Introductionmentioning

confidence: 99%