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Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis.

McKinley-Barnard S, Andre T, Morita M, Willoughby DS - J Int Soc Sports Nutr (2015)

Bottom Line: Due to its effects on nitric oxide synthase (NOS), reduced glutathione (GSH) may protect against the oxidative reduction of NO.In phase two, plasma NOx with L-citrulline + GSH was significantly greater than control and L-citrulline (p < 0.05).However, nitrite and NOx for L-citrulline + GSH were significantly greater at 30 min post-exercise when compared to placebo (p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Health, Human Performance, and Recreation, Baylor University, Exercise and Biochemical Nutritional Lab, 76798 Waco, TX USA.

ABSTRACT

Background: Nitric oxide (NO) is endogenously synthesized from L-arginine and L-citrulline. Due to its effects on nitric oxide synthase (NOS), reduced glutathione (GSH) may protect against the oxidative reduction of NO. The present study determined the effectiveness of L-citrulline and/or GSH on markers indicative of NO synthesis in in vivo conditions with rodents and humans and also in an in vitro condition.

Methods: In phase one, human umbilical vein endothelial cells (HUVECs) were treated with either 0.3 mM L-citrulline, 1 mM GSH (Setria®) or a combination of each at 0.3 mM. In phase two, Sprague-Dawley rats (8 weeks old) were randomly assigned to 3 groups and received either purified water, L-citrulline (500 mg/kg/day), or a combination of L-citrulline (500 mg/kg/day) and GSH (50 mg/kg/day) by oral gavage for 3 days. Blood samples were collected and plasma NOx (nitrite + nitrate) assessed. In phase three, resistance-trained males were randomly assigned to orally ingest either cellulose placebo (2.52 g/day), L-citrulline (2 g/day), GSH (1 g/day), or L-citrulline (2 g/day) + GSH (200 mg/day) for 7 days, and then perform a resistance exercise session involving 3 sets of 10-RM involving the elbow flexors. Venous blood was obtained and used to assess plasma cGMP, nitrite, and NOx.

Results: In phase one, nitrite levels in cells treated with L-citrulline and GSH were significantly greater than control (p < 0.05). In phase two, plasma NOx with L-citrulline + GSH was significantly greater than control and L-citrulline (p < 0.05). In phase three, plasma cGMP was increased, but not significantly (p > 0.05). However, nitrite and NOx for L-citrulline + GSH were significantly greater at 30 min post-exercise when compared to placebo (p < 0.05).

Conclusions: Combining L-citrulline with GSH augments increases in nitrite and NOx levels during in vitro and in vivo conditions.

No MeSH data available.


Related in: MedlinePlus

From phase three, an illustration of plasma citrulline levels in humans following seven days of supplementation with L-citrulline and/or GSH. Results indicated that L-citrulline (CIT) and a combination of CIT + GSH produced significant increases in plasma CIT immediately after and 30 min post-exercise compared to groups supplemented with cellulose (PLC) and GSH. The symbol * indicates a significant increase compared to PLC and the symbol † indicates a significant increase compared to GSH (p < 0.05)
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Fig5: From phase three, an illustration of plasma citrulline levels in humans following seven days of supplementation with L-citrulline and/or GSH. Results indicated that L-citrulline (CIT) and a combination of CIT + GSH produced significant increases in plasma CIT immediately after and 30 min post-exercise compared to groups supplemented with cellulose (PLC) and GSH. The symbol * indicates a significant increase compared to PLC and the symbol † indicates a significant increase compared to GSH (p < 0.05)

Mentions: Since no supplementation was involved at the baseline testing session, as expected, no significant differences between groups or time points (p > 0.05) for plasma L-citrulline and L-arginine were observed. However, at the follow-up testing session following seven 7 days of supplementation significant increases for plasma L-arginine and L-citrulline were noted. For L-arginine, no significant differences occurred between placebo and GSH at any time points (p > 0.05). However, at the immediate post-exercise time point L-citrulline was significantly greater than placebo and GSH, whereas L-citrulline + GSH was greater than GSH (p < 0.05). In addition, at 30 min post-exercise L-citrulline and L-citrulline + GSH were both significantly greater than placebo and GSH (p < 0.05) (Fig. 4). For plasma L-citrulline, L-citrulline and L-citrulline + GSH were both significantly greater than placebo and GSH immediately post-exercise and at 30 min post-exercise (p < 0.05) (Fig. 5).Fig. 4


Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis.

McKinley-Barnard S, Andre T, Morita M, Willoughby DS - J Int Soc Sports Nutr (2015)

From phase three, an illustration of plasma citrulline levels in humans following seven days of supplementation with L-citrulline and/or GSH. Results indicated that L-citrulline (CIT) and a combination of CIT + GSH produced significant increases in plasma CIT immediately after and 30 min post-exercise compared to groups supplemented with cellulose (PLC) and GSH. The symbol * indicates a significant increase compared to PLC and the symbol † indicates a significant increase compared to GSH (p < 0.05)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4472409&req=5

Fig5: From phase three, an illustration of plasma citrulline levels in humans following seven days of supplementation with L-citrulline and/or GSH. Results indicated that L-citrulline (CIT) and a combination of CIT + GSH produced significant increases in plasma CIT immediately after and 30 min post-exercise compared to groups supplemented with cellulose (PLC) and GSH. The symbol * indicates a significant increase compared to PLC and the symbol † indicates a significant increase compared to GSH (p < 0.05)
Mentions: Since no supplementation was involved at the baseline testing session, as expected, no significant differences between groups or time points (p > 0.05) for plasma L-citrulline and L-arginine were observed. However, at the follow-up testing session following seven 7 days of supplementation significant increases for plasma L-arginine and L-citrulline were noted. For L-arginine, no significant differences occurred between placebo and GSH at any time points (p > 0.05). However, at the immediate post-exercise time point L-citrulline was significantly greater than placebo and GSH, whereas L-citrulline + GSH was greater than GSH (p < 0.05). In addition, at 30 min post-exercise L-citrulline and L-citrulline + GSH were both significantly greater than placebo and GSH (p < 0.05) (Fig. 4). For plasma L-citrulline, L-citrulline and L-citrulline + GSH were both significantly greater than placebo and GSH immediately post-exercise and at 30 min post-exercise (p < 0.05) (Fig. 5).Fig. 4

Bottom Line: Due to its effects on nitric oxide synthase (NOS), reduced glutathione (GSH) may protect against the oxidative reduction of NO.In phase two, plasma NOx with L-citrulline + GSH was significantly greater than control and L-citrulline (p < 0.05).However, nitrite and NOx for L-citrulline + GSH were significantly greater at 30 min post-exercise when compared to placebo (p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Health, Human Performance, and Recreation, Baylor University, Exercise and Biochemical Nutritional Lab, 76798 Waco, TX USA.

ABSTRACT

Background: Nitric oxide (NO) is endogenously synthesized from L-arginine and L-citrulline. Due to its effects on nitric oxide synthase (NOS), reduced glutathione (GSH) may protect against the oxidative reduction of NO. The present study determined the effectiveness of L-citrulline and/or GSH on markers indicative of NO synthesis in in vivo conditions with rodents and humans and also in an in vitro condition.

Methods: In phase one, human umbilical vein endothelial cells (HUVECs) were treated with either 0.3 mM L-citrulline, 1 mM GSH (Setria®) or a combination of each at 0.3 mM. In phase two, Sprague-Dawley rats (8 weeks old) were randomly assigned to 3 groups and received either purified water, L-citrulline (500 mg/kg/day), or a combination of L-citrulline (500 mg/kg/day) and GSH (50 mg/kg/day) by oral gavage for 3 days. Blood samples were collected and plasma NOx (nitrite + nitrate) assessed. In phase three, resistance-trained males were randomly assigned to orally ingest either cellulose placebo (2.52 g/day), L-citrulline (2 g/day), GSH (1 g/day), or L-citrulline (2 g/day) + GSH (200 mg/day) for 7 days, and then perform a resistance exercise session involving 3 sets of 10-RM involving the elbow flexors. Venous blood was obtained and used to assess plasma cGMP, nitrite, and NOx.

Results: In phase one, nitrite levels in cells treated with L-citrulline and GSH were significantly greater than control (p < 0.05). In phase two, plasma NOx with L-citrulline + GSH was significantly greater than control and L-citrulline (p < 0.05). In phase three, plasma cGMP was increased, but not significantly (p > 0.05). However, nitrite and NOx for L-citrulline + GSH were significantly greater at 30 min post-exercise when compared to placebo (p < 0.05).

Conclusions: Combining L-citrulline with GSH augments increases in nitrite and NOx levels during in vitro and in vivo conditions.

No MeSH data available.


Related in: MedlinePlus