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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.


From phase three, an illustration of plasma arginine 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 arginine 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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Fig4: From phase three, an illustration of plasma arginine 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 arginine 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 arginine 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 arginine 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

Fig4: From phase three, an illustration of plasma arginine 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 arginine 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.