The effect of L-ornithine hydrochloride ingestion on human growth hormone secretion after strength training

Demura, Shinichi; Yamada, Takayoshi; Yamaji, Shunsuke; Komatsu, Michiharu

doi:10.4236/abb.2010.11002

Cited by 15 publications

(15 citation statements)

References 15 publications

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“…In addition, although many effects of its ingestion have not been clarified, the L-ornithine promotes growth hormone release by stimulating the pituitary gland (Evain-Brion et al, 1982;Demura et al, 2010). Additionally, L-ornithine is one product of arginase enzyme activity on L-arginine, and is also related to the creation of urea.…”

Section: Introductionmentioning

confidence: 99%

The effect of L-ornithine hydrochloride ingestion on performance during incremental exhaustive ergometer bicycle exercise and ammonia metabolism during and after exercise

et al. 2010

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Objectives: L-ornithine has an important role in ammonia metabolism via the urea cycle. This study aimed to examine the effect of L-ornithine hydrochloride ingestion on performance during incremental exhaustive ergometer bicycle exercise and ammonia metabolism during and after exercise. Subjects/Methods: In all, 14 healthy young adults (age: 22.2 ± 1.0 years, height: 173.5 ± 4.6 cm, body mass: 72.5 ± 12.5 kg) who trained regularly conducted incremental exhaustive ergometer bicycle exercises after L-ornithine hydrochloride supplementation (0.1 g/kg, body mass) and placebo conditions with a cross-over design. The exercise time (sec) of the incremental ergometer exercise, exercise intensity at exhaustion (watt), maximal oxygen uptake (ml per kg per min), maximal heart rate (beats per min) and the following serum parameters were measured before ingestion, 1 h after ingestion, just after exhaustion and 15 min after exhaustion: ornithine, ammonia, urea, lactic acid and glutamate. All indices on maximal aerobic capacity showed insignificant differences between both the conditions. Results: Plasma ammonia concentrations just after exhaustion and at 15 min after exhaustion were significantly more with ornithine ingestion than with placebo. Plasma glutamate concentrations were significantly higher after exhaustion with ornithine ingestion than with placebo. Conclusions: It was suggested that, although the ingestion of L-ornithine hydrochloride before the exercise cannot be expected to improve performance, it does increase the ability to buffer ammonia, both during and after exercise.

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Section: Introductionmentioning

confidence: 99%

The effect of L-ornithine hydrochloride ingestion on performance during incremental exhaustive ergometer bicycle exercise and ammonia metabolism during and after exercise

et al. 2010

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“…These results may suggest that the effect of Orn on mTORC1 signaling was not exerted through its metabolite, citrulline. Another mechanism behind the effects of Orn on mTORC1 pathway was thought to be through growth hormone release, because it was reported that Orn has the potential to stimulate growth hormone release (9). Orn administration tended to increase plasma growth hormone levels (P＜0.1, Table 1).…”

Section: Discussionmentioning

confidence: 99%

“…In pharmacological therapy, Orn is used to decrease blood ammonia levels and reduce the symptoms of hepatic encephalopathy associated with liver cirrhosis (6). In addition, many human studies have indicated several beneficial effects of Orn, including attenuation of fatigue evoked by exercise or alcohol consumption (7,8), stimulation of growth hormone release (9), and improvements in sleep disturbance (10,11). Furthermore, a report indicated that the addition of Orn to a basal diet induced the blood growth hormone level and the rate of protein synthesis in the liver and gastrocnemius muscle (12).…”

Section: Introductionmentioning

confidence: 99%

The Effect of L-Ornithine on the Phosphorylation of mTORC1 Downstream Targets in Rat Liver

Kokubo

Maeda

Tazumi

et al. 2015

JFN

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A non-protein amino acid, L-ornithine (Orn), has been shown to stimulate the urea cycle and tissue protein synthesis in the liver. The purpose of the current study was to assess whether Orn affects the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) pathway, which is involved in protein synthesis. Primary cultured cells isolated from Wistar rat liver were incubated in an amino acid-free medium, followed by addition of Orn for 3 h. The cell lysate was subjected to immunoblotting to evaluate the phosphorylation of downstream targets of mTORC1, including p70S6K, S6, and 4EBP1. To assess the involvement of mTORC1 for the effect of Orn, the cells were pretreated with the mTOR inhibitor rapamycin before the addition of Orn and the cell lysate was subjected to immunoblotting. We next examined whether the effects of Orn were exerted in vivo. Orn was orally administered to 18 h food-deprived rats, the blood and the livers were collected at 1 and 3 h after administration for immunoblotting. Orn treatment for primary cultured cells for 3 h enhanced the phosphorylation of p70S6K, S6, and 4EBP1. In addition, rapamycin blocked the effects of Orn completely (p70S6K and S6) or partially (4EBP1). The oral administration of Orn to the rat also augmented the phosphorylation of mTORC1 downstream targets notably in S6 at 1 h. Our findings demonstrate that Orn has the potential to induce the phosphorylation of downstream targets of mTORC1 in the rat liver. This may be mediated by the augmentation of mTORC1 activity.

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“…Therefore, it is possible that there is no significant difference in serum growth hormone concentration between both conditions. However, Demura et al [16] examined the effect of L-ornithine hydrochloride ingestion on enhancement of growth hormone secretion after resistance exercise using 10 male adults and reported that serum growth hormone concentration 30 min after resistance exercise in the L-ornithine hydrochloride ingestion condition was greater than that of the placebo ingestion condition. The inconsistency between the results of the present and previous studies may be attributed to measurement time of growth hormone rather than quantity of L-ornithine hydrochloride ingestion.…”

Section: Discussionmentioning

confidence: 99%

“…Bucci et al [15] examined the effect of L-ornithine hydrochloride ingestion on enhancement of growth hor-mone secretion in body builders and reported that the blood concentration of growth hormone increased with L-ornithine hydrochloride ingestion. Moreover, Demura et al [16] examined the effect of L-ornithine hydrochloride ingestion before resistance exercise on postexercise growth hormone secretion in ten healthy male adults and reported that blood concentration of growth hormone after resistance exercise was greater in the L-ornithine hydrochloride ingestion condition than the placebo ingestion condition. Namely, enhanced growth hormone secretion has been suggested by not only ingestion of free amino acids such as L-ornithine, but also subsequent resistance exercise after amino acid ingestion.…”

Section: Introductionmentioning

confidence: 99%

L-ornithine hydrochloride ingestion increased carbohydrate oxidation but not lipid oxidation during submaximal endurance exercise following resistance exercise

Demura¹,

Yamada²,

Yamaji³

et al. 2013

ABB

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This study aimed to examine the effect of L-ornithine hydrochloride ingestion on lipid oxidation during submaximal endurance exercise following resistance exercise. Ten healthy young male adults with no history of regular resistance exercise (age: 26.0 +/- 4.4) conducted resistance exercise after L-ornithine hydrochloride or placebo ingestion (0.1 g/kg). Subjects exercised for 60 min on an ergometer at 50% VO_2peak 120 min after resistance exercise. Plasma ornithine concentrations measured immediately, 120min and 180min after resistance exercise in the L-ornithine hydrochloride ingestion condition were significantly greater than those in the placebo condition. No significant difference was found in serum growth hor mone concentrations between both conditions (F = 4.4, p = 0.065). Serum free fatty acid concentrations were significantly greater immediately after submaximal ergometer bicycle exercise in both conditions than those before ingestion, immediately after resistance exercise and 120min after resistance exercise (F = 43.4, p < 0.001, 300% - 508%), but no significant difference was found between both conditions (F = 3.6, p = 0.090). A similar trend was observed in serum ketone bodies as well. Although total energy production during submaximal ergometer exercise did not significantly differ (t = 0.74, p = 0.238), a significant difference was found in energy production via carbohydrate and lipid oxidation; the former was greater in the Lornithine hydrochloride ingestion condition (t = 1.89, p = 0.046, d = 0.44, 106%), and the latter was greater in the placebo condition (t = 1.89, p = 0.046, d = 0.78%, 145%). From the above, L-ornithine hydrochloride ingestion may not affect lipid metabolism during submaximal endurance exercise following resistance exercise. It may be involved in energy production via carbohydrate oxidation with glucogenic amino acid.

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The effect of L-ornithine hydrochloride ingestion on human growth hormone secretion after strength training

Cited by 15 publications

References 15 publications

The effect of L-ornithine hydrochloride ingestion on performance during incremental exhaustive ergometer bicycle exercise and ammonia metabolism during and after exercise

The effect of L-ornithine hydrochloride ingestion on performance during incremental exhaustive ergometer bicycle exercise and ammonia metabolism during and after exercise

The Effect of L-Ornithine on the Phosphorylation of mTORC1 Downstream Targets in Rat Liver

L-ornithine hydrochloride ingestion increased carbohydrate oxidation but not lipid oxidation during submaximal endurance exercise following resistance exercise

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