Category: l-arginine


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

Source

Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.

Abstract

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 -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.

PMID:
20717126
[PubMed – indexed for MEDLINE]
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Abstract
In the present study, oral supplementation of l-arginine in rats was evaluated for its anti-stress and adaptogenic activity using the cold (5°C)–hypoxia (428 mmHg)–restraint (C-H-R) animal model. A dose-dependent study of l-arginine was carried out at doses of 12.5, 25.0, 50.0, 100.0, 200.0 and 500.0 mg/kg body weight, administered orally 30 min prior to C-H-R exposure. The time taken by the rat to attain a rectal temperature of 23°C (Trec 23°C) during C-H-R exposure and its recovery to Trec 37°C at normal atmospheric pressure and 32 ± 1°C were used as biomarkers of anti-stress and adaptogenic activity. Biochemical parameters related to lipid peroxidation, anti-oxidants, cell membrane permeability, nitric oxide and stress, with and without administration of the least effective l-arginine dose, were measured in rats on attaining Trec 23°C and Trec 37°C. The least effective adaptogenic dose of l-arginine was 100.0 mg/kg body weight. The C-H-R exposure of control rats, on attaining Trec 23°C, resulted in a significant increase in plasma malondialdehyde (MDA), blood lactate dehydrogenase (LDH) and a decrease in blood catalase (CAT) and plasma testosterone levels. On recovery (Trec 37°C) of control rats, there was a further decrease in CAT and plasma testosterone, and an increase in LDH. l-Arginine supplementation resulted in a significant decrease in plasma MDA, an increase in blood superoxide dismutase (SOD), CAT levels maintained at control values and a lower increase in LDH compared with controls (45.3 versus 58.5% and 21.5 versus 105.2%) on attaining Trec 23°C during C-H-R exposure and on recovery to Trec 37°C. The results suggested that l-arginine possesses potent anti-stress activity during C-H-R exposure and recovery from C-H-R-induced hypothermia.
Keywords: hypoxia, cold, rectal temperature, oxidative stress
Introduction
Biological stress is a response to physical, chemical, biological and emotional changes, consisting of a pattern of metabolic and behavioral reactions that helps to strengthen the organism (1). During stressful situations, the energy requirement of the organism is increased, resulting in enhanced generation of free radicals (24). Free radicals cause oxidation of nucleic acids and proteins. Free radicals also damage biomembranes, reflected by increased lipid peroxidation, thereby compromising cell integrity and function. During this process, the ability of the body’s defense system to combat the oxidative stress may diminish due to reduced anti-oxidants. If the stress level increases beyond the threshold limit of an individual, it results in decreased performance and stress-induced disorders. The management of unusual stress therefore has acquired enormous significance in day-to-day life. Such a management does not endeavor to eliminate stress but rather to raise the threshold level of the organism beyond which stress would start injuring and disturbing life processes. It is possible to support the body’s adaptation by using food supplements, dietary elements, herbs and minerals for increasing physical and mental performance, described in various oriental systems of medicine including the ancient Indian medical system Ayurveda. Such substances have been described as ‘adaptogens’ (5). In strenuous conditions, the physical performance of the organism is dependent on the availability of appropriate macro- and micronutrients required in excess on account of their increased utilization during stressful situations (6). Supplementation with various macro- and micronutrient and herbal preparations has been evaluated for their adaptogenic activity during exposure to a stressful environment (710).
It has been suggested that amino acid supplementation might be able to increase human performance to a limited extent (11). An amino acid mixture supplementation was observed to enhance adrenocortical hormone, luteinizing hormone and follicle-stimulating hormone response to corticotropin-releasing hormone in athletes (12). Under certain metabolic, developmental or pathophysiological conditions, some of the non-essential amino acids become essential and are designated as ‘conditionally essential’. Arginine and glutamine are known to be conditionally essential amino acids (13). l-Arginine plays important roles in the urea cycle, protein synthesis, as a precursor of polyamines and creatine, and as a substrate for synthesis of nitric oxide (NO). NO was shown to be an endothelial-derived relaxation factor, a vasodilator, which acted as a modulator of vascular tone to regulate blood flow and blood pressure (14). NO is also involved in enhancement of the thermogenic function of brown adipose tissue in rats (15). It is interesting that herbs with adaptogenic activity, e.g. Panax ginseng, have been shown to contain large amounts of arginine (16).
It was shown that endogenous plasma arginine levels decreased significantly after 30 min immobilization stress and remain suppressed during a 3.5 h post-stress period (17). In burn patients, there was a higher rate of arginine loss from the body and supplementation of arginine was required to maintain homeostasis and promote recovery (18). In the present study, the anti-stress and adaptogenic effect, if any, of l-arginine supplementation was studied in rats subjected to a comprehensive and generalized stress of cold (5°C)–hypoxia (428 mmHg)– restraint (C-H-R) (19).

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Investigation of the effects of oral supplementation of arginine in the increase of muscular strength and mass

Gerseli Angeli
1, Turibio Leite de Barros1, Daniel Furquim Leite de Barros2 and Marcelo Lima3

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ABSTRACT
Introduction: Oral administration of arginine has been associated with physical performance improvement due to probable decrease of muscular fatigue derived from the vasodilatation factor of the nitric oxide over the skeletal muscles.
Objective: to evaluate the effects of oral administration of L-Arginine during an exercise program with weights. Methods: 20 male individuals, randomly divided in two groups: A and B, were submitted to eight weeks of training with weights (three times per week). Group A used 3 grams of L-Arginine + vitamin C during the eight weeks and group B used only vitamin C (control group).
Results: After eight weeks of training, group A presented body weight values and lean mass significantly higher (p < 0.05), body fat percentage significantly lower (p< 0.05), and strength of lower limbs significantly higher (p < 0.05), while group B did not present significant differences for the same period.
Conclusion: Oral administration of arginine associated with a training program with weights increased the stimuli of the exercise to the skeletal muscles level, enabling hence, increase of
muscular strength and mass.