Metabolic changes induced by maximal exercise in human subjects following L-carnitine administration

Siliprandi, N.; Lisa, Fabio Di; Pieralisi, G; Ripari, Patrizio; Maccari, F.; Menabò, Roberta; Giamberardino, M. A.; Vecchiet, L

doi:10.1016/0304-4165(90)90147-o

Cited by 67 publications

(42 citation statements)

References 21 publications

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“…Levels of urinary excretion of carnitine were significantly higher in supplemented rats than in nonsupplemented rats with and without exercise. These results were in agreement with those of Siliprandi et al ( 25 ). Nuesch et al.…”

Section: Free Carnitine Concentrations In the Serum And Urinesupporting

confidence: 93%

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Beef Extract Supplementation Increases Leg Muscle Mass and Modifies Skeletal Muscle Fiber Types in Rats

Yoshihara

Wakamatsu

Kawabata

et al. 2006

J Nutr Sci Vitaminol

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SummaryThe objective of this research was to investigate the effects of beef extract on fat metabolism, muscle mass and muscle fiber types in rats. We also investigated the synergetic effect of endurance exercise. Twenty-four male rats weighing about 270 g were assigned to two diets containing 0 or 6% beef extract (BE). Half the rats fed each diet were subjected to compulsory exercise (CE) for 30 min every other day. After 4 weeks feeding, the blood was collected and various organs were dissected. The muscle fiber type of the soleus and extensor digitorum longus (EDL) muscles were evaluated by histochemical and electrophoretical analyses. Rats supplemented with BE showed a decrease in fat content in liver and abdomen and an increase in the activity of carnitine palmitoyl transferase II in liver. BE as well as exercise increased the relative weights of both soleus and EDL. BE alone and BE plus CE did not affect the distribution of muscle fiber types in soleus. BE without exercise decreased in type IIb of EDL from 54% to 44% with compensatory increase in type IIa from 41% to 49% and type I from 5% to 7% compared with the nonsupplemented, nonexercised control group. No synergetic effect on a fast to slow fiber conversion due to the combination of BE and CE was detected. Thus, BE supplement increased muscle mass and slow type fiber in EDL. The effects of BE supplement on muscle characteristics were similar to those of exercise. Key Words beef extract, fat metabolism, muscle fiber type, muscle mass, L -carnitine A great deal of research has been done to elucidate the general nutritional value of beef on the growth of human subjects and the effects of protein quality and exercise on the growth and protein metabolism of animals and human beings ( 1-3 ). However, existing information about the nutritional effects of beef extract on muscle metabolism is not sufficient.Skeletal muscle is composed of at least three fiber types on the basis of their contractile and energy metabolic properties; type I fibers exhibit an aerobic energy metabolism (slow-twitch fiber), type IIb fibers are predominantly glycolytic (fast-twitch fiber) and type IIa fibers are the intermediate type exhibiting both oxidative and glycolytic metabolisms. Lipids are easily accumulated in type I fibers ( 4 ), while glycogen depletion occurs primarily in the type II ( 5 ). It is well known that cross-reinnervation, electrical stimulation or exercise evokes the fiber type conversion, although the molecular mechanisms mediating the transformation are not clearly elucidated ( 6 , 7 ). This means that skeletal muscle cells possess a capacity to respond and adapt to metabolic changes imposed by physical stimulation or neural stimulation. Concretely, endurance exercise requiring the consumption of oxygen stimulates a shift to the slow twitch, oxidative muscle fibers ( 8 ). The fiber types of adult skeletal muscle are closely related to energy metabolic characteristics as described above. Nutrition-induced regulation in mRNA levels for a number of metabolic gene...

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Section: Free Carnitine Concentrations In the Serum And Urinesupporting

confidence: 93%

“…Serum carnitine concentration in BEϩCE were not appreciably affected by the supplement. However, the previous reports showed that carnitine in serum was less susceptible than in urine (25,33).…”

Section: Discussionmentioning

confidence: 88%

Beef Extract Supplementation Increases Leg Muscle Mass and Modifies Skeletal Muscle Fiber Types in Rats

Yoshihara

Wakamatsu

Kawabata

et al. 2006

J Nutr Sci Vitaminol

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“…(19), com o objetivo de avaliar o aumento da oxidação de ácidos graxos em repouso, tenha encontrado resultados positivos com doses semelhantes à do presente estudo (aproximadamente 2 gramas/dia), outros, utilizando infusão intravenosa de carnitina (3 g) (17), doses inferiores e semelhantes (20)(21)(22), ou doses superiores (4 a 6 g/dia), não confirmaram tais achados (23)(24).…”

Section: Discussionunclassified

A suplementação de L-carnitina não promove alterações na taxa metabólica de repouso e na utilização dos substratos energéticos em indivíduos ativos

Coelho

Mota

Ravagnani

et al. 2010

Arq Bras Endocrinol Metab

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A suplementação de L-carnitina não promove alterações na taxa metabólica de repouso e na utilização dos substratos energéticos em indivíduos ativosThe supplementation of L-carnitine does not promote alterations in the resting metabolic rate and in the use of energetic substrates in physically active individuals To investigate the effects of L-carnitine supplementation, over thirty days, on the resting metabolic rate (RMR) and oxidation of free fatty acids (FFA) under rested or exercised conditions. Subjects and methods: Twenty-one overweight active volunteers (40 to 58 years old) were randomized into two groups: supplemented (GS; N = 11; 1,8 g/day of L-carnitine) or placebo (GP; N = 10; maltodextrin). Caloric intake, anthropometry, RMR, VO 2max , respiratory exchange ratio and plasma FFA were measured. Results: No significant changes were found in the caloric intake (-244,66 vs. -126,00 kcal/day), body composition (-0.07 vs. -0.17 kg/m 2 ), RMR (0.06 vs. -0.02 kcal/day), respiratory exchange ratio at rest (3.69 vs. -1.01) and exercise (0.01 vs. -0.01) or VO 2max (0.50 vs. 1.25 mL/kg/min) between GS and GP. Plasma FFA levels were increased under resting conditions only in the GP group (0.27), but no significant changes were observed before or after physical activity in any of the groups. Conclusion: Supplementation with L-carnitine caused no changes in the variables analyzed in this study. Arq Bras Endocrinol Metab. 2010;54(1):37-44

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“…It enhances the oxidative utilization of glucose through the acceleration of pyruvate uptake in mitochondria [7]. Moreover, it improves insulin sensitivity in skeletal muscles by promoting glucose utilization [8].…”

Section: Introductionmentioning

confidence: 99%

Decreased level of serum carnitine might lead to arteriosclerosis progression via the accumulation of advanced glycation end products in maintenance hemodialysis patients

et al. 2017

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Background: Carnitine is reported to improve insulin resistance and reduce oxidative stress. Hyperglycemia and increased oxidative stress are well known to promote the production of advanced glycation end products (AGEs) that can lead to arteriosclerosis in patients with maintenance hemodialysis (HD). In the present study, we aimed to determine whether decreased level of serum carnitine accelerated arteriosclerosis and to clarify the relationships between carnitine, AGEs, and arteriosclerosis in HD patients. Methods: We recruited 116 patients (65 men and 51 women, 62 ± 13 years) undergoing HD three times a week. We measured pre-HD serum free carnitine prior to the first weekly session. AGE level was quantitatively evaluated by measuring skin autofluorescence (SAF) with AGE reader. Arteriosclerosis was evaluated by measuring carotid intima-media thickness (cIMT). Relationships between free carnitine, SAF, and cIMT were analyzed, and significant limiting factors for arteriosclerosis were identified using univariate and multivariate regression analyses. Results: Free carnitine ranged from 14.9 to 53.3 μmol/L (mean, 28.6 ± 8.1 μmol/L). Free carnitine was negatively correlated with SAF (r = − 0.223, P = 0.017) and cIMT (r = − 0.252, P = 0.006). SAF was positively correlated with cIMT (r = 0.263, P = 0.005). Free carnitine was identified as a significant independent limiting factor for cIMT (β = -0.194, P = 0.037). Conclusions: Decreased level of serum carnitine might lead to the progression of arteriosclerosis via the AGE accumulation in HD patients.

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Metabolic changes induced by maximal exercise in human subjects following L-carnitine administration

Cited by 67 publications

References 21 publications

Beef Extract Supplementation Increases Leg Muscle Mass and Modifies Skeletal Muscle Fiber Types in Rats

Beef Extract Supplementation Increases Leg Muscle Mass and Modifies Skeletal Muscle Fiber Types in Rats

A suplementação de L-carnitina não promove alterações na taxa metabólica de repouso e na utilização dos substratos energéticos em indivíduos ativos

Decreased level of serum carnitine might lead to arteriosclerosis progression via the accumulation of advanced glycation end products in maintenance hemodialysis patients

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